Experimental Results

We present benchmarks of majority optimizations discussed. We also present the same benchmarks performed on IA-32 and Alpha system where possible to give an comparison of effectivity of individual optimizations on these architectures. We hope this to be useful to apply earlier published results on compiler optimization (such as [FDO]) to the new platform and give a guide of what optimizations are most important. We also present results with two different optimization levels -- the standard optimization (-O2) used by the majority of distributions today and aggressive optimization (-O3 -ftracer -funroll-loops -funit-at-a-time with profile feedback) we found to give best overall SPEC score.

We did use modified prerelease of GCC 3.3 as used by SuSE Linux 8.2 for AMD64. All the runs were performed on SuSE Linux on dedicated machines, however important amount of random noise remains (especially for benchmarks Mesa, Gzip, Perl and Twolf). Due to time limitations the benchmarks were performed with one iteration only except for the benchmarks in the Table and that were computed with 3 iterations. Because the runs were not done on final hardware and because we didn't satisfy the conditions for reportable runs in all tests, we present relative numbers only.

Each table is divided into two sections -- first part includes optimizations enabled by default at given optimization level, while the other part contains optimization that user needs to enable by hand either because they are ineffective, inappropriate for given settings or does not obey the language standards. Each table also contains comparison of two runs with equal settings in the first line to present rough approximation of the noise in the numbers. Both performance and sizes of the stripped binaries are presented. The numbers always represent relative speedup (or code size increase) from the run with the specified feature disabled to the run with specified feature enabled. For instance -fomit-frame-pointer run in the table compare performance of -O2 -fno-omit-frame-pointer to -O2 -fomit-frame-pointer. The benchmark ``standard optimization'' compare -O0 to -O2.

The Following benchmarks were performed:

aggressive optimization

compare performance of unoptimized code (-O0) to the aggressive optimization settings described above.

all prologue using move

eliminate use of all push and pop operations in the prologues and epilogues except for cases where single register is saved. See Section 2.2.

-fasynchronous-unwind-tables

enable production of DWARF2 unwind information. See Section 2.3.

-fbranch-probabilities

enable profile feedback based optimizations. We implemented majority of transformations described on [FDO] with the exception of function in-lining and switch statement expansion.

-fgcse

enable global optimizers including (limited form of) partial redundancy elimination, load motion, constant propagation and copy propagation. GCC does contain loop invariant hoisting and extended basic block based value numbering pass making the global optimizers partly redundant.

-fguess-branch-probability

enable optimizations driven by static profile estimation. The profile is estimated by methods based on [profile] when profile feedback is not available.

-finline-functions

enable function in-lining.

-fold-unroll-loops

enable old loop unroller that actually unrolls some loops on Alpha.

-fomit-frame-pointer

enable elimination of frame pointer by using stack pointer instead. See Section 2.2.

-foptimize-sibling-calls

transform call to leaf function into jump.

-fpeel-loops

enable loop peeling.

-fpic

produce position independent code. See Section 2.7.

-freorder-blocks

enable intra-function basic block reordering and duplication based on significantly modified software trace cache algorithm [STC].

-fschedule-insns2

enable post-register allocation local scheduling. See Section 3.3.

-fschedule-insns

enable pre-register allocation region scheduling (not available for IA-32 and AMD64).

-fstrength-reduce

enable strength reduction.

-fstrict-aliasing

enable ANSI-C type based aliasing.

full sized loads and moves

avoids use of instructions initializing just portion of the destination registers. See Section 3.2 and 3.1.

-ftracer

enable super-block formation using algorithm similar to [FDO]. The super-blocks are unified again after optimizations by cross-jumping pass so this transformation is not used to improve scheduling as commonly described in the literature. It is aimed to improve CSE and other transformation by simplifying the control flow.

-funit-at-a-time

enable optimizations on whole compilation unit. At the moment GCC perform stronger function in-lining (in-lining of small functions called before defined and static functions called once) and use register calling conventions for static functions on IA-32. Only effective for C compiler.

-funroll-all-loops

enable loop unrolling of all small enough loops in the hot spots.

-funroll-loops

enable loop unrolling for loops with known induction variable. While working on the paper we noticed that our new implementation has important flaw avoiding loops from being unrolled on Alpha architecture.

-m64

enable 64-bit code generation (used in comparisons relative to IA-32 code).

-mfpmath=sse

eliminate use SSE(2) instruction set for scalar floating point calculations.

-mcmodel

controls code and data segment size limits. See Section 2.7.

-mred-zone

enable use of 128 bytes below stack pointer for local data. See Section 2.2.

partial SSE moves

eliminate use of movlpd for double precision loads and movsd for register to register moves. See Section 3.2.

prologue using move

eliminate use of hot push and pop operations in the prologues and epilogues. See Section 2.2.

standard optimization

compare performance of unoptimized code (-O0) to the standard optimization settings (-O2).

Table 1: Compilation Time Cost (AMD Opteron)

options	slowdown
	0.00%
-fstrict-aliasing	-1.13%
-fasynchronous-unwind-tables	-0.38%
-freorder-blocks	0.00%
-fomit-frame-pointer	0.37%
-mred-zone	0.38%
-mfpmath=sse	0.75%
-maccumulate-outgoing-args	0.75%
-foptimize-sibling-calls	0.76%
-fguess-branch-probabilities	1.54%
-fschedule-insns2	2.33%
-fgcse	6.88%
-ffast-math	-1.88%
-ftracer	0.00%
-frename-registers	0.74%
-funroll-loops	3.38%
-fpic	3.39%
-funroll-all-loops	5.32%
-mcmodel=medium	2.27%
-fbranch-probabilities	142.74%

Performance (relative speedups in percents):

Table: 64-bit SPECint 2000 with Standard Optimization (AMD Opteron)

options	gzip	vpr	gcc	mcf	crafty	parser	eon	perl	gap	vortex	bzip2	twolf	avg
	1.32	0.14	-0.45	-0.45	-0.17	0.19	0.41	0.11	0.60	0.28	0.27	-0.54	0.13
standard optimization	105.37	82.29	90.55	12.06	87.14	58.23	451.70	97.05	101.18	75.30	142.14	55.99	93.40
-fguess-branch	4.40	4.45	2.90	0.00	2.73	0.19	5.58	5.96	7.43	21.60	2.56	-1.46	4.10
probabilities
-fschedule-insns2	1.62	1.44	2.40	0.22	0.32	0.78	4.90	1.28	-0.45	4.34	0.41	0.93	1.46
-fstrict-aliasing	1.48	4.62	1.93	0.00	3.68	0.58	-2.34	1.75	0.75	4.27	4.79	-2.34	1.19
-mfpmath=sse	1.93	3.98	-0.23	0.00	-0.09	-0.39	2.11	0.00	1.81	3.94	0.27	0.80	1.06
prologue using move	-0.74	0.14	0.34	0.00	4.04	0.98	-0.43	1.43	0.30	5.71	-0.28	0.13	0.93
full sized loads and moves	-1.76	-0.29	-0.46	0.88	0.96	-0.20	24.90	-1.52	-0.45	-1.04	0.97	-3.61	0.93
-fgcse	1.17	4.28	-1.77	1.35	0.48	1.38	2.33	1.75	-1.48	1.55	1.26	0.13	0.92
-foptimize	1.62	0.43	-0.12	0.00	3.33	0.00	2.33	-0.35	1.51	2.44	0.27	0.26	0.92
sibling-calls
-finline-functions	1.62	0.71	0.22	1.11	0.32	3.08	0.30	-1.04	0.58	-0.99	2.21	0.67	0.65
-fomit-frame-pointer	0.29	1.58	0.56	0.67	5.00	1.57	-3.03	3.07	-0.60	0.47	2.41	-3.48	0.39
-freorder-blocks	3.61	-0.29	-0.57	0.22	2.31	-0.78	0.72	4.06	0.75	3.45	1.84	-5.31	0.39
-maccumulate-	1.92	-0.58	0.78	0.45	0.24	-0.39	1.04	-0.12	-0.60	-1.13	0.13	0.80	0.26
outgoing-args
-mred-zone	1.47	0.14	1.35	-0.23	1.30	-0.20	-1.73	0.00	-0.30	-0.29	0.55	-0.67	0.13
partial SSE moves	-0.30	5.89	-0.92	0.00	0.07	0.00	-1.17	0.00	0.00	-0.10	-0.14	-3.36	-0.27
aggressive optimization	6.34	4.97	8.81	0.67	1.29	25.43	24.14	12.29	7.51	5.69	5.42	4.65	8.40
-fbranch-probabilities	5.95	1.71	7.13	0.22	-0.65	16.76	2.98	3.90	0.14	6.95	0.27	3.73	4.07
-funroll-all-loops	4.16	0.42	5.60	0.00	-4.28	0.77	16.42	4.02	1.35	0.57	1.82	1.46	2.50
-funroll-loops	3.71	0.28	4.17	0.00	0.08	0.58	15.35	1.61	1.35	-4.78	0.55	3.32	2.23
all prologue using move	-0.60	0.56	2.38	-0.23	-0.40	0.58	3.73	3.19	-0.15	-4.29	0.55	4.68	1.05
-ffast-math	1.78	0.28	0.67	0.00	-0.25	-0.20	0.31	-0.81	0.15	2.67	1.12	2.64	0.78
-frename-registers	-0.15	0.56	-0.68	0.00	0.08	0.58	1.34	-2.19	-0.76	-1.25	0.97	4.92	0.65
-funit-at-a-time	0.89	2.71	0.79	0.45	0.72	0.38	0.00	-0.47	-0.45	0.68	0.69	-0.93	0.39
-ftracer	3.12	0.14	1.57	0.00	1.13	-0.20	1.76	0.91	-7.81	-3.83	1.40	2.40	0.13
-cmodel=medium	-4.30	-1.00	-0.45	0.00	-10.84	0.00	2.18	-3.57	-5.83	-6.27	-2.23	-0.27	-2.51
-fpic	-9.11	-1.72	-1.68	0.89	-18.21	-0.78	-1.36	-16.79	-3.76	-15.16	-6.18	-1.48	-6.20

File size (relative increase of the size of stripped binaries in percents):

options	gzip	vpr	gcc	mcf	crafty	parser	eon	perl	gap	vortex	bzip2	twolf	total
standard optimization	-11.24	-23.04	-23.74	-20.59	-17.13	-13.77	-13.71	-20.00	-36.54	-9.42	-15.83	-39.29	-22.31
-maccumulate-	-0.42	-4.02	-3.47	-3.34	-0.35	-3.30	-3.15	-3.29	-4.31	-3.60	5.16	-2.51	-3.25
outgoing-args
-fomit-frame-pointer	-0.26	1.72	-1.13	-0.20	0.04	-3.76	-1.94	-1.24	-1.07	2.08	-0.08	-0.99	-0.71
-fstrict-aliasing	0.00	-0.68	-0.15	0.00	0.00	0.00	0.22	0.00	-0.34	-0.66	0.00	-5.02	-0.40
-mred-zone	0.00	-0.11	-0.19	0.00	-0.02	0.00	-0.76	0.59	-0.02	0.00	0.00	-0.04	-0.09
-fschedule-insns2	0.00	0.02	-0.15	0.00	0.01	0.00	0.02	0.00	0.00	0.02	0.00	-0.07	-0.05
-fgcse	-0.11	0.04	-0.16	0.19	0.03	0.11	0.44	0.68	-0.01	-0.68	0.00	-1.16	-0.05
-foptimize	0.00	-0.03	0.08	0.00	-0.02	0.00	-0.76	0.48	-0.16	-0.01	-0.23	-0.10	-0.03
sibling-calls
partial SSE moves	0.00	0.00	0.00	0.00	0.00	0.00	0.16	0.00	0.00	0.00	0.00	0.01	0.02
full sized loads and moves	0.00	0.00	0.04	0.00	1.21	0.00	0.00	0.00	0.08	-0.01	0.00	0.11	0.08
-mfpmath=sse	0.00	-0.64	-0.15	0.00	0.00	0.00	2.34	-0.01	0.00	0.00	0.00	-1.64	0.13
prologue using move	-0.11	1.06	1.01	0.00	1.26	-0.34	0.91	0.84	1.44	2.55	0.00	0.16	1.14
-freorder-blocks	7.06	2.71	4.43	0.00	4.05	3.67	1.07	5.72	3.42	5.60	10.89	4.22	4.19
-finline-functions	-0.73	1.15	8.85	-0.20	0.24	28.60	0.12	6.55	3.37	1.99	29.84	0.68	5.49
-fguess-branch	7.00	4.41	5.82	0.00	3.60	3.34	2.64	6.67	5.85	8.74	10.89	3.97	5.66
probabilities
-fasynchronous	7.12	10.28	7.38	6.31	3.76	17.16	4.83	9.26	9.04	7.88	18.14	5.34	7.71
unwind-tables
-fbranch-probabilities	-4.91	-2.07	-2.20	0.82	0.11	0.02	-2.44	-3.92	-3.74	-4.72	-7.30	-1.80	-2.85
-funit-at-a-time	-22.64	-4.95	-1.50	0.00	0.00	0.00	0.00	-0.82	-0.08	-0.01	0.00	-0.10	-1.09
-ffast-math	0.00	-0.03	0.00	0.00	0.00	0.00	0.00	-0.68	0.00	-0.02	0.00	0.01	-0.09
-frename-registers	0.00	0.26	0.97	0.00	0.28	0.00	1.99	0.68	0.24	0.04	0.00	1.83	0.78
all prologue using move	-0.73	4.14	1.14	-0.96	-0.33	2.18	1.35	0.87	1.60	0.52	-0.77	2.38	1.17
-ftracer	0.00	1.27	1.29	0.00	0.13	0.00	2.50	2.01	2.46	1.31	0.00	1.54	1.56
-funroll-loops	13.30	7.92	3.18	1.34	4.22	7.11	1.26	2.70	12.57	0.02	9.82	8.70	4.21
-funroll-all-loops	13.30	9.53	4.29	24.50	4.71	14.20	1.43	3.38	15.76	0.66	9.82	14.40	5.71
-fpic	12.11	6.53	3.62	1.14	21.40	9.38	1.92	6.48	15.53	9.16	7.06	16.66	7.55
-mcmodel=medium	13.62	8.10	7.10	0.00	17.57	7.44	6.35	8.29	8.35	6.64	9.90	13.33	8.09
aggressive optimization	-14.42	4.03	21.89	5.12	6.44	44.45	-0.47	8.80	7.38	0.73	40.05	3.93	11.08

Performance (relative speedups in percents):

Table: 64-bit SPECfp 2000 with Standard Optimization (AMD Opteron)

options	wupwise	swim	mgrid	applu	mesa	art	equake	ammp	sixtrack	apsi	avg
	-0.28	-0.13	0.00	0.00	0.23	-2.07	0.14	0.00	0.00	0.00	-0.16
standard optimization	102.22	54.49	633.14	220.37	79.20	22.69	90.76	111.08	204.34	192.64	142.52
-mfpmath=sse	9.30	0.12	3.31	2.38	11.68	102.55	0.28	8.32	11.53	6.01	12.43
-fguess-branch-	7.62	0.00	6.42	2.78	7.48	0.42	-2.23	-1.27	-0.29	4.72	2.75
probabilities
partial SSE moves	2.86	0.13	2.95	3.21	3.34	-3.26	0.86	3.11	3.86	3.33	2.12
full sized loads and moves	2.13	0.26	1.35	1.98	6.38	0.69	0.00	2.00	1.45	1.55	1.78
-fstrict-aliasing	0.00	0.12	0.00	0.19	2.22	5.22	-2.23	0.90	0.00	5.08	1.44
-fschedule-insns2	2.23	0.00	7.72	0.78	0.34	-1.40	-2.50	0.90	4.50	1.01	1.28
-freorder-blocks	0.97	0.12	0.18	0.19	13.09	2.28	0.28	0.00	-1.42	0.00	1.28
-fomit-frame-pointer	2.51	0.00	4.53	0.38	-0.58	-1.80	-1.13	0.90	-0.29	3.63	0.95
prologue using move	-3.24	0.00	0.00	0.00	3.58	0.69	0.00	-0.14	0.00	0.00	0.15
-finline-functions	0.13	0.12	0.00	0.19	1.85	-1.51	1.84	-0.52	0.28	-0.17	0.15
-foptimize	0.82	0.12	0.18	0.19	-0.46	-0.97	0.00	0.12	0.00	0.00	0.00
sibling-calls
-mred-zone	0.00	0.00	0.00	0.38	0.57	0.97	-2.10	-0.26	0.00	0.16	0.00
-maccumulate-	0.55	-0.13	0.18	0.00	0.45	-3.46	0.00	0.00	-0.29	0.33	-0.16
outgoing-args
-fgcse	1.37	0.00	-7.19	-5.15	-0.23	0.69	0.42	-0.64	-4.14	-2.13	-1.71
aggressive optimization	5.57	-0.91	6.60	4.26	4.14	-1.93	7.96	3.58	10.63	-2.34	3.15
-funroll-all-loops	2.72	-0.13	1.88	2.32	-1.50	5.58	0.42	3.58	-0.29	1.16	1.58
-funroll-loops	2.72	0.00	1.88	2.51	-0.92	2.67	2.13	3.58	-0.29	1.16	1.57
-ffast-math	0.81	0.00	0.00	2.13	1.26	-3.16	0.99	4.74	0.57	1.50	0.94
all prologue using move	4.18	0.00	-0.39	0.19	0.23	-0.98	1.86	-0.27	1.14	0.34	0.63
-fbranch-probabilities	-3.44	0.12	-0.94	0.38	15.14	-1.40	-0.15	-0.65	0.85	-3.35	0.15
-funit-at-a-time	0.13	0.12	-0.19	0.00	3.93	-3.54	0.14	0.12	0.00	-0.17	0.15
-frename-registers	-3.54	-0.26	5.66	-0.39	-7.23	-1.11	4.97	3.46	0.86	-0.34	0.15
-ftracer	-0.82	0.00	0.00	0.00	-2.87	-2.35	-0.15	0.77	0.86	-0.67	-0.64
-cmodel=medium	2.73	-0.26	-0.19	-0.39	-3.69	-0.83	-0.72	-1.03	-14.95	-0.17	-1.90
-fpic	0.95	0.00	0.37	-0.97	1.72	-0.29	0.71	-0.13	-20.98	-0.17	-1.90

File size (relative increase of the size of stripped binaries in percents):

options	wupwise	swim	mgrid	applu	mesa	art	equake	ammp	sixtrack	apsi	total
standard optimization	-25.71	-26.52	-36.03	-60.14	-34.62	-15.82	-33.14	-32.33	-38.32	-30.33	-36.85
-maccumulate-	-1.63	-0.71	-1.83	-0.71	-3.40	-2.07	-1.80	-2.77	-1.12	-1.17	-1.89
outgoing-args
-fschedule-insns2	0.00	0.00	0.00	0.05	0.00	0.00	0.00	0.02	-0.43	0.00	-0.21
-mred-zone	0.00	0.00	-0.19	-2.31	-0.13	-0.08	-0.14	-0.12	-0.03	-0.12	-0.14
-fgcse	0.00	-8.64	-4.00	-10.19	-0.74	1.91	-0.38	0.00	1.70	-3.61	-0.07
-fstrict-aliasing	0.00	0.00	0.00	0.00	-0.13	0.07	0.00	-0.05	0.00	0.00	-0.04
-foptimize	0.00	0.00	0.00	0.00	-0.24	0.00	0.00	0.04	-0.02	0.68	-0.02
sibling-calls
full sized loads and moves	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.40	0.00	0.75	0.08
-fomit-frame-pointer	0.00	0.47	0.75	-1.97	-0.05	0.39	-0.14	0.37	0.12	5.74	0.43
partial SSE moves	0.00	0.23	0.00	0.71	0.79	0.00	0.00	0.24	0.43	0.89	0.53
prologue using move	-0.28	0.00	0.00	0.11	1.78	0.00	0.00	0.26	-0.02	0.70	0.53
-freorder-blocks	0.00	0.47	0.00	0.11	2.44	0.00	0.00	2.62	0.86	1.37	1.38
-mfpmath=sse	0.00	2.16	0.00	6.26	-1.57	0.00	-0.14	3.19	2.65	4.39	1.60
-fguess-branch	-0.28	1.43	0.00	-0.36	5.10	12.16	10.56	3.04	0.41	1.19	2.09
probabilities
-finline-functions	0.00	0.00	0.00	0.00	5.39	19.96	0.13	0.42	1.29	1.50	2.45
-fasynchronous-	9.34	3.15	6.75	1.92	10.46	16.55	13.01	6.21	1.25	3.83	4.67
unwind-info
-fbranch-probabilities	0.64	0.15	0.76	0.19	-5.23	0.70	0.61	-2.11	-0.28	-0.06	-1.58
-ffast-math	0.00	-0.95	0.00	0.58	-0.83	-13.04	-0.27	-5.57	0.86	0.00	-0.35
-funit-at-a-time	0.00	0.00	0.00	0.00	-0.07	0.00	0.00	-0.03	0.00	0.00	-0.03
all prologue using move	-0.28	1.40	0.37	1.29	0.78	-1.02	-0.40	2.26	0.61	1.96	0.86
-ftracer	0.00	0.00	0.00	0.00	2.37	0.07	0.00	5.45	0.43	3.35	1.51
-frename-registers	0.00	0.47	0.00	2.65	1.78	0.00	0.00	2.60	2.58	0.86	2.10
-funroll-loops	1.93	24.69	6.32	6.42	7.95	20.05	0.65	11.14	3.02	6.63	5.63
-funroll-all-loops	1.93	24.69	7.25	6.42	8.19	20.05	2.35	11.14	3.02	6.63	5.73
-fpic	0.45	0.23	0.93	2.24	5.92	9.28	7.71	4.91	8.04	3.75	6.51
-mcmodel=medium	0.09	4.93	0.00	7.49	3.53	0.85	1.83	5.45	24.62	6.36	14.32
aggressive optimization	71.81	164.20	125.37	57.30	11.28	97.53	52.54	12.91	26.21	34.10	26.45

Performance (relative speedups in percents):

Table: 64-bit SPECint 2000 with Aggressive Optimization (AMD Opteron)

options	gzip	vpr	gcc	mcf	crafty	parser	eon	perl	gap	vortex	bzip2	twolf	avg
	-0.28	-0.41	0.20	-0.45	0.00	-0.16	0.00	-0.11	0.84	0.00	0.13	0.38	0.12
aggressive optimization	112.35	91.73	103.60	14.72	86.01	97.56	589.65	130.46	111.79	74.46	151.98	56.79	106.81
-fbranch-probabilities	8.40	2.62	10.71	0.22	3.38	21.72	27.67	27.67	14.24	10.37	4.39	-1.56	9.49
-fguess-branch...
full sized loads and moves	1.00	0.67	-0.53	0.00	0.97	-0.48	56.39	1.79	0.71	0.62	0.13	4.64	4.61
-fbranch-probabilities	2.69	0.00	5.62	-0.45	2.62	19.85	-0.92	11.94	4.06	2.29	1.07	0.51	3.77
-m64	9.90	0.27	3.39	-22.19	42.29	-2.13	45.66	0.30	-1.25	6.29	8.28	-13.33	3.38
-funroll-loops	1.69	0.54	0.41	0.22	0.88	1.41	16.94	7.59	0.56	1.73	0.93	4.62	3.12
-freorder-blocks	4.95	1.22	4.51	0.22	3.89	1.89	2.40	13.06	-0.56	-1.42	0.40	1.15	2.48
-fomit-frame-pointer	0.13	0.00	2.19	0.44	2.03	1.73	2.31	5.38	-0.28	1.08	1.47	5.05	2.10
-fstrict-aliasing	-0.56	4.80	0.82	0.44	1.04	1.89	1.61	2.08	1.72	1.64	5.88	1.15	1.85
-finline-functions	-0.42	0.54	1.55	2.02	1.86	5.21	1.01	-0.31	0.42	3.62	3.13	2.75	1.85
-ftracer	-0.69	-0.27	0.30	0.00	1.12	0.78	5.20	3.93	0.14	0.27	0.53	4.90	1.60
-fschedule-insns2	0.27	2.62	0.41	0.22	4.24	0.46	2.57	1.55	0.99	3.34	1.61	0.64	1.47
-mred-zone	-0.42	0.13	0.61	0.66	0.96	0.31	-1.33	1.56	-0.56	7.01	-0.14	3.56	1.22
-fgcse	2.70	4.06	1.14	-0.23	3.47	-0.77	-0.51	-0.82	2.29	1.27	0.93	0.25	1.10
-mfpmath=sse	-0.28	2.48	-0.52	0.66	1.95	0.78	9.05	0.72	0.14	-2.80	-0.14	1.42	1.10
-frename-registers	-0.42	1.22	-1.13	-0.45	4.24	0.46	-1.90	-0.72	-0.97	1.91	1.47	4.81	0.98
-funit-at-a-time	-0.56	3.50	-1.23	0.22	1.12	0.93	0.16	-1.42	2.73	3.43	-0.27	2.64	0.98
prologue using move	-0.43	0.54	1.06	0.43	1.06	0.79	-2.75	1.89	3.63	6.29	-0.14	-0.26	0.86
partial SSE moves	-0.29	0.81	0.10	-0.44	0.00	0.63	0.00	0.62	0.00	0.26	-0.40	4.78	0.73
-foptimize	0.00	-0.14	0.61	0.22	0.96	0.78	1.96	0.00	-1.93	-1.86	-0.27	3.15	0.60
sibling-calls
-maccumulate-	-0.28	0.94	-0.11	-0.23	2.53	0.46	1.18	-0.72	2.43	-0.81	0.13	0.63	0.48
outgoing-args
-fstrength-reduce	-0.42	0.26	-1.22	0.00	0.64	0.00	-0.59	-1.81	0.42	4.30	-0.14	-0.13	0.00
all prologue using move	-1.13	-0.27	-0.32	-0.22	1.28	0.94	6.46	-0.11	1.54	-1.33	0.39	0.50	0.61
-ffast-math	-0.28	0.40	-1.24	-0.23	-1.92	0.00	0.08	0.10	0.56	1.34	-0.27	-3.56	-0.73
-fpeel-loops	0.00	0.13	-1.13	0.22	-1.20	-0.62	0.08	-1.34	-1.69	-3.86	-0.40	-0.26	-0.73
-funroll-all-loops	0.00	0.13	0.10	0.00	-0.48	-0.16	-0.84	2.04	-2.12	-5.58	0.26	-7.90	-1.70
-cmodel=medium	-5.12	-1.21	-2.97	0.44	-10.61	-0.78	-1.09	0.00	0.28	-4.85	-0.67	-7.74	-3.28
-fpic	-12.73	-1.89	-2.36	-0.89	-13.88	-6.96	-4.36	-12.79	-2.11	-18.23	-10.03	-8.87	-8.12

File size (relative increase of the size of stripped binaries in percents):

options	gzip	vpr	gcc	mcf	crafty	parser	eon	perl	gap	vortex	bzip2	twolf	total
aggressive optimization	-24.01	-19.87	-6.95	-16.43	-11.81	24.89	-14.11	-12.48	-31.74	-8.77	17.87	-36.91	-13.57
-fbranch-probabilities	-12.51	-8.07	-5.50	-0.95	-2.64	-2.55	-5.80	-7.77	-14.58	-5.56	-12.11	-10.22	-7.10
-maccumulate-	-1.79	-1.55	-2.33	-1.44	-0.87	-2.85	-3.31	-1.77	-4.10	-3.78	3.05	-1.85	-2.58
outgoing-args
-fgcse	0.73	-1.16	-1.95	-0.37	-1.92	-1.27	-0.32	-0.59	-0.38	-0.68	-0.06	-3.33	-1.23
-fomit-frame-pointer	-1.38	1.02	-0.81	-0.91	-0.27	-1.20	-1.94	-1.43	-1.10	1.41	-0.06	-1.20	-0.72
-fstrict-aliasing	0.12	-1.14	-0.11	-0.73	0.00	0.36	0.36	-0.58	-0.56	-0.66	0.00	-5.14	-0.46
-mred-zone	0.00	-0.06	-0.06	0.00	0.00	0.00	-0.34	-0.04	-0.02	0.12	0.00	-0.05	-0.05
-fschedule-insns2	-0.07	-0.06	-0.07	-0.19	0.01	0.07	0.00	-0.01	-0.02	0.00	0.00	-0.04	-0.03
-foptimize	0.06	-0.04	0.10	0.00	0.00	-0.04	-0.45	-0.20	0.13	-0.01	-0.06	-0.05	-0.03
sibling-calls
-fstrength-reduce	0.24	0.11	-0.01	0.18	0.01	0.03	-0.02	0.00	0.10	0.00	0.00	0.12	0.02
partial SSE moves	0.00	0.27	0.00	0.00	0.00	0.01	0.24	0.00	0.00	0.00	0.00	0.01	0.03
full sized loads and moves	0.18	0.09	0.17	0.00	0.00	0.40	0.01	0.00	0.13	0.00	0.00	0.07	0.10
-mfpmath=sse	0.00	-1.35	-0.05	-0.55	-0.14	-0.08	3.34	-0.58	0.00	0.00	0.00	-1.39	0.15
prologue using move	0.00	0.07	0.14	0.00	-0.05	0.40	-0.02	0.45	0.28	0.37	-0.06	0.06	0.20
-funroll-loops	1.73	0.98	0.34	3.97	1.51	3.22	0.28	0.04	1.00	0.00	0.00	0.77	0.52
-freorder-blocks	0.24	0.11	1.05	-0.55	0.00	-0.04	0.20	0.63	0.36	0.00	0.00	0.21	0.53
-frename-registers	1.35	1.18	1.26	0.00	1.47	0.71	2.27	0.67	0.62	0.66	0.00	2.19	1.16
-ftracer	0.67	1.36	1.57	2.61	2.02	2.29	0.44	1.30	1.61	2.01	0.00	0.58	1.43
-fbranch-probabilities	6.09	4.09	5.60	5.44	6.03	9.87	-0.21	3.90	3.58	4.49	7.78	3.27	4.40
-fguess-branch...
-funit-at-a-time	-14.10	2.25	12.02	0.00	2.04	5.62	0.00	4.14	6.08	2.66	7.60	1.92	5.94
-m64	16.48	-2.64	8.02	18.47	-19.00	15.52	0.25	11.38	9.65	-5.69	8.64	-3.44	3.90
-finline-functions	8.71	7.94	23.54	2.80	3.51	39.11	-0.09	11.96	9.86	4.17	39.65	2.71	12.98
-ffast-math	0.00	-0.02	0.03	0.00	0.00	0.00	0.00	-0.05	0.00	-0.02	0.00	0.01	0.00
-funroll-all-loops	0.00	0.23	0.04	2.18	0.00	1.26	0.00	0.57	0.09	0.00	0.00	-2.94	0.03
-fpic	16.27	4.69	-6.01	0.18	17.87	-21.91	0.96	1.39	6.50	7.12	-21.77	14.97	0.38
-fpeel-loops	1.57	0.39	0.35	1.63	1.98	5.80	0.00	0.57	0.96	0.00	0.00	1.25	0.66
all prologue using move	2.18	2.85	1.30	1.45	0.26	2.63	2.31	1.71	2.95	2.77	-0.72	2.62	1.91
-mcmodel=medium	14.15	9.85	7.56	19.12	18.58	7.95	5.97	9.93	9.90	7.91	21.15	12.94	9.01

Performance (relative speedups in percents):

Table: 64-bit SPECfp 2000 with Aggressive Optimization (AMD Opteron)

options	wupwise	swim	mgrid	applu	mesa	art	equake	ammp	sixtrack	apsi	avg
	1.30	0.00	0.89	0.56	-5.34	-0.28	0.00	-0.13	-1.29	1.21	-0.16
aggressive optimization	101.11	53.87	686.79	225.30	101.38	26.80	100.81	123.51	225.00	180.97	149.23
-m64	5.00	-0.27	16.25	9.79	28.55	83.54	-1.31	19.17	28.33	20.86	19.34
-mfpmath=sse	13.97	0.12	2.40	2.33	7.04	100.28	1.79	16.64	22.22	5.67	13.80
-fbranch-probabilities	-0.83	0.39	10.83	3.96	19.62	2.23	-0.28	6.85	2.24	0.70	3.98
-fguess-branch...
partial SSE moves	1.58	0.13	2.18	1.76	0.70	1.27	-2.51	3.17	6.14	2.54	1.74
-fstrict-aliasing	0.13	0.00	0.00	0.00	-0.90	4.49	1.37	5.49	0.00	4.71	1.73
full sized loads and moves	-2.25	0.26	3.31	1.16	4.29	2.40	2.92	0.86	2.25	0.89	1.57
-fschedule-insns2	0.13	0.12	13.06	0.57	-9.93	1.53	-0.68	5.49	3.71	1.58	1.41
-ftracer	0.27	0.00	-0.19	-0.19	-2.85	0.97	1.79	1.10	0.00	0.34	0.15
-mred-zone	-0.95	0.00	-0.19	1.15	-2.32	0.13	1.09	0.00	0.00	0.00	-0.16
prologue using move	-1.53	0.13	-0.18	-0.20	0.91	-0.84	-0.14	0.00	0.00	-0.18	-0.16
-frename-registers	0.00	0.00	4.52	-0.76	-12.07	1.83	3.21	1.84	1.39	-1.03	-0.31
-fbranch-probabilities	-1.61	0.00	-0.37	-0.57	7.36	-0.83	-0.14	-0.49	0.83	-4.16	-0.32
-fomit-frame-pointer	-1.08	0.00	0.54	0.95	-11.17	-0.69	0.68	0.85	0.00	1.94	-0.62
-finline-functions	0.00	0.12	-0.19	0.00	-12.12	2.97	1.23	0.36	-0.28	0.00	-0.77
-maccumulate-	3.20	-0.13	0.00	-0.19	-9.94	-0.70	0.40	-0.13	-0.28	0.00	-0.78
outgoing-args
-freorder-blocks	1.08	0.00	-0.19	-0.19	-11.27	1.11	0.13	1.72	0.00	0.00	-0.78
-funroll-loops	-2.43	-0.13	0.00	1.34	-11.02	0.83	0.54	3.25	0.00	0.34	-0.78
-foptimize	-1.20	0.00	-0.37	0.00	-13.20	0.97	-0.28	-0.49	0.00	0.34	-1.23
sibling-calls
-fstrength-reduce	-1.85	0.00	-0.37	5.20	-13.15	-0.14	0.95	-0.85	1.39	-2.04	-1.23
-funit-at-a-time	-0.96	0.12	-0.19	-0.19	-11.26	0.00	1.09	0.00	0.00	0.00	-1.24
-fgcse	-1.46	-0.39	-7.52	-4.36	-12.53	1.26	0.40	-0.13	-1.63	-3.19	-3.02
-ffast-math	-2.01	0.00	-0.19	1.13	14.99	-0.70	2.16	1.45	-0.83	2.94	1.86
-fpeel-loops	9.94	0.00	-0.19	0.18	0.00	-0.83	-1.22	0.00	0.00	-0.18	0.62
-funroll-all-loops	-0.41	0.12	0.00	-0.19	0.00	0.98	-1.49	-0.13	0.00	0.17	-0.16
-fpic	5.42	-0.13	0.00	-0.95	14.84	0.55	-1.76	0.00	-20.67	-0.18	-0.63
all prologue using move	-5.90	0.00	-0.89	-0.39	0.20	-0.28	0.54	-0.62	0.00	0.17	-0.78
-cmodel=medium	-0.54	-0.13	-0.55	-1.71	9.68	-3.19	-1.76	-3.88	-16.53	-1.22	-2.01

File size (relative increase of the size of stripped binaries in percents):

options	wupwise	swim	mgrid	applu	mesa	art	equake	ammp	sixtrack	apsi	total
aggressive optimization	-16.48	-15.91	-34.31	-57.92	-33.11	8.36	-29.40	-26.61	-36.44	-25.42	-34.22
-fbranch-probabilities	0.55	-8.26	-2.73	-3.79	-12.90	-10.98	-9.59	-7.97	-4.00	-7.95	-7.22
-maccumulate-	-1.93	-0.62	-1.78	-0.78	-3.49	-0.97	-0.99	-1.92	-0.80	-1.19	-1.67
outgoing-args
-mred-zone	0.00	-0.21	-0.37	-2.03	-0.77	-0.13	-0.13	-0.03	-0.01	-0.30	-0.30
-fstrict-aliasing	0.00	0.00	0.00	0.00	-0.75	6.80	-10.04	0.00	0.00	-0.18	-0.27
-fgcse	0.00	-8.64	-4.00	-10.19	-0.74	1.91	-0.38	0.00	1.70	-3.61	-0.07
-fschedule-insns2	0.00	0.00	0.00	0.00	-0.10	0.00	0.00	0.00	0.00	0.00	-0.03
prologue using move	-0.09	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.06	0.00
-foptimize	0.00	0.00	-0.37	0.00	-0.18	0.00	0.00	0.00	0.36	0.10	0.13
sibling-calls
full sized loads and moves	0.00	0.00	0.00	0.00	0.00	0.00	0.12	0.00	0.34	0.08	0.17
-freorder-blocks	0.00	0.00	0.00	0.00	0.03	0.24	0.49	0.00	0.42	-0.09	0.21
-funit-at-a-time	0.00	0.00	0.00	0.00	0.11	0.12	4.67	1.85	0.00	0.00	0.23
-fomit-frame-pointer	8.70	0.82	0.91	-1.92	-0.51	-0.73	-0.38	0.51	0.40	5.13	0.57
-fstrength-reduce	0.00	0.00	0.18	-0.51	0.03	0.00	0.12	0.00	1.20	0.12	0.59
partial SSE moves	0.00	0.20	0.18	0.39	0.77	0.60	0.00	0.00	0.82	0.23	0.65
-ftracer	11.68	0.41	-1.26	0.00	0.03	0.36	0.87	5.54	0.00	0.92	0.70
-funroll-loops	10.37	14.33	2.03	2.81	0.03	6.59	3.06	2.39	0.35	2.96	1.09
-fbranch-probabilities	12.12	15.26	2.69	3.25	0.02	19.33	5.59	8.65	0.43	4.67	1.92
-fguess-branch...
-frename-registers	8.99	0.82	0.54	2.99	2.38	1.85	1.76	2.69	2.57	1.58	2.53
-finline-functions	0.00	0.00	0.00	0.00	5.92	18.22	4.94	2.41	1.27	1.84	2.75
-mfpmath=sse	8.70	2.96	2.03	8.08	-0.75	6.59	3.99	5.54	5.28	5.13	3.72
-m64	45.40	201.01	156.05	26.51	17.41	39.81	27.06	23.41	28.79	38.22	28.68
-ffast-math	0.00	-0.83	0.00	0.94	-0.85	-6.44	-4.84	-8.23	0.40	-0.18	-0.81
-funroll-all-loops	0.00	0.00	0.00	0.00	0.00	0.24	0.61	0.00	0.00	0.00	0.01
-fpeel-loops	0.00	0.00	0.00	1.39	0.00	0.36	1.36	0.00	0.00	0.12	0.07
all prologue using move	-0.49	8.82	1.79	1.28	2.22	8.41	0.99	2.15	0.36	4.23	1.49
-fpic	0.65	-6.38	2.35	1.11	5.32	-3.71	13.13	2.23	6.58	3.47	5.21
-mcmodel=medium	0.00	9.45	2.17	7.98	5.43	10.44	11.27	5.24	23.48	6.72	14.49

Performance (relative speedups in percents):

Table: 32-bit SPECint 2000 with Aggressive Optimization (AMD Opteron)

options	gzip	vpr	gcc	mcf	crafty	parser	eon	perl	gap	vortex	bzip2	twolf	avg
	1.06	-0.14	0.42	0.69	0.11	0.00	-0.13	0.20	-0.28	0.85	0.71	3.52	0.75
aggressive optimization	96.74	76.81	73.11	14.74	56.38	83.61	349.45	111.06	98.34	71.82	122.25	67.09	89.12
-march=i386 to k8	5.23	8.41	3.45	0.17	9.02	6.80	82.00	-0.52	0.41	14.78	2.45	8.52	10.08
-fbranch-probabilities	8.34	2.37	12.33	1.40	4.25	7.49	17.57	14.35	8.99	12.75	6.47	0.87	7.37
-fguess-branch...
-fbranch-	2.94	0.41	10.33	0.17	2.91	5.43	0.61	8.82	2.41	8.26	6.45	0.77	3.89
probabilities
-fomit-frame-pointer	8.64	1.36	0.84	0.17	2.26	6.51	0.73	0.41	4.58	2.66	6.25	3.78	3.26
-fgcse	1.99	1.52	-2.27	-0.69	0.57	-4.36	5.14	8.00	2.67	2.93	1.86	2.98	1.77
-finline-functions	0.90	1.96	0.00	2.84	2.91	6.62	1.86	0.82	1.41	3.34	1.87	1.78	2.17
-ftracer	0.15	1.94	4.58	-0.52	-0.34	-2.23	3.94	9.70	0.13	1.74	3.05	0.77	1.78
-fschedule-insns2	2.30	2.22	2.47	-0.35	2.32	0.15	0.12	1.87	-0.69	2.04	1.73	2.70	1.52
-funit-at-a-time	-0.60	8.91	3.47	-0.18	2.55	-1.50	0.12	7.50	-1.10	1.83	0.28	-0.67	1.39
-freorder-blocks	1.99	0.68	7.88	-0.87	3.52	0.76	-0.37	1.24	-0.83	2.23	2.01	-1.00	1.26
-funroll-loops	-0.31	-0.55	0.00	0.34	0.22	-1.79	6.77	0.72	0.69	2.71	1.14	3.53	1.25
-march=ppro to k8	5.91	-1.89	2.37	0.34	0.45	-4.22	2.63	0.30	1.11	0.38	2.75	2.60	1.13
-maccumulate-	0.60	-0.28	0.53	0.00	2.67	-2.08	5.95	2.62	0.27	4.06	1.00	-2.15	0.88
outgoing-args
-frename-registers	-0.30	1.65	-0.94	-1.04	0.68	-2.67	-1.57	0.00	-0.14	2.74	0.85	5.49	0.75
-foptimize	-0.16	0.27	2.24	0.34	-0.34	-1.93	-1.21	-0.11	0.69	1.93	0.56	0.11	0.25
sibling-calls
-fstrict-aliasing	1.07	-1.37	0.21	1.39	-0.12	0.00	0.12	0.10	0.55	0.09	0.71	0.55	0.25
-fstrength-reduce	-0.16	0.54	-0.53	-1.04	0.57	-2.51	0.12	0.00	-1.10	-1.14	0.28	1.10	-0.25
-funroll-all-loops	3.10	-0.28	0.31	-0.87	0.11	2.73	0.49	2.98	0.68	1.14	-0.15	1.98	1.00
-mfpmath=sse	1.83	2.32	1.28	-1.38	0.11	0.45	0.36	0.51	1.39	0.94	0.85	0.32	0.75
-ffast-math	-0.31	1.09	0.63	0.34	-0.46	0.15	0.12	0.72	0.55	0.86	0.42	0.44	0.50
-fpeel-loops	2.29	0.00	-0.32	-0.52	0.90	3.17	0.00	0.10	-3.43	-0.29	0.70	-1.20	0.00
-fpic	-20.49	-5.64	-17.55	-3.28	-29.60	-28.19	-10.27	-29.75	-23.00	-35.03	-25.65	-17.66	-20.81

File size (relative increase of the size of stripped binaries in percents):

options	gzip	vpr	gcc	mcf	crafty	parser	eon	perl	gap	vortex	bzip2	twolf	total
aggressive optimization	-18.85	-6.25	3.51	-21.10	2.34	33.46	-4.21	-6.83	-22.83	-2.91	33.80	-22.33	-4.05
-fbranch-probabilities	-14.82	-8.93	-5.82	0.67	-1.96	-3.46	-5.89	-7.95	-14.56	-3.10	-11.81	-10.11	-6.87
-fgcse	1.21	-1.15	-1.23	0.00	2.31	-0.93	0.20	0.52	0.21	0.51	-1.59	-1.60	-0.28
-foptimize	0.07	0.11	0.09	0.00	0.07	0.00	-1.44	0.05	0.01	-0.03	-1.18	-0.02	-0.14
sibling-calls
-fstrict-aliasing	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00
-fstrength-reduce	0.21	0.09	0.02	0.00	0.05	-0.29	0.03	0.09	0.12	0.00	0.00	-0.19	0.02
-fschedule-insns2	-0.15	0.21	-0.07	0.00	-0.07	0.00	1.63	-0.02	-0.04	-0.01	0.00	0.03	0.15
-march=ppro to k8	-2.15	1.33	-0.40	0.00	-0.36	0.00	5.56	-0.29	-0.49	0.10	-1.18	0.31	0.40
-funroll-loops	3.06	0.81	0.32	0.00	1.16	2.91	0.08	0.21	0.88	0.08	2.31	0.31	0.48
-frename-registers	0.49	0.48	0.52	0.00	0.51	0.00	1.42	0.81	0.22	0.10	1.02	0.31	0.55
-freorder-blocks	-0.08	-0.06	1.22	0.00	0.50	-0.03	0.17	0.82	0.29	0.10	0.53	0.22	0.62
-fomit-frame-pointer	-1.77	2.89	0.39	0.00	-0.14	0.77	4.52	-0.79	0.17	2.38	-2.80	-0.11	0.95
-ftracer	0.00	1.33	1.78	0.00	4.56	2.91	0.31	2.07	1.71	2.56	0.29	0.31	1.80
-fbranch-probabilities	6.98	3.72	6.73	0.67	9.29	9.37	-0.26	4.48	3.81	4.67	6.41	2.35	4.93
-fguess-branch...
-maccumulate-	1.29	6.40	6.00	0.00	1.95	2.47	0.38	2.07	4.64	19.88	3.13	4.36	5.87
outgoing-args
-funit-at-a-time	-11.69	6.01	13.64	0.00	2.27	6.00	0.00	4.45	7.07	2.65	6.53	1.86	6.58
-march=i386 to k8	1.43	9.46	9.78	0.00	3.65	6.00	8.00	4.13	6.70	21.21	4.02	8.63	9.24
-finline-functions	10.90	8.91	28.84	0.00	3.79	39.55	0.16	13.26	10.95	4.65	50.44	2.30	14.46
-ffast-math	0.00	-0.79	0.01	0.00	-0.02	0.00	0.00	-0.13	0.00	-1.23	0.00	-0.06	-0.21
-funroll-all-loops	0.00	0.25	0.05	0.00	0.07	2.83	0.00	0.03	0.07	0.03	1.19	0.21	0.15
-fpeel-loops	2.19	1.15	0.39	0.00	2.81	6.13	0.00	0.21	0.88	0.02	1.25	1.61	0.72
-fpic	12.59	6.19	-4.89	0.00	14.80	-27.60	10.58	4.43	1.15	1.35	-21.21	9.83	0.84
-mfpmath=sse	-0.08	1.15	-0.03	0.00	-0.06	0.00	10.10	0.17	0.00	0.00	1.19	-1.80	1.13

Performance (relative speedups in percents):

Table: 32-bit SPECfp 2000 with Aggressive Optimization (AMD Opteron)

options	wupwise	swim	mgrid	applu	mesa	art	equake	ammp	sixtrack	apsi	avg
	0.13	0.00	0.00	-0.21	0.28	2.57	-0.14	0.00	6.00	0.00	0.72
aggressive optimization	77.83	27.22	445.45	148.97	56.22	-30.46	92.25	101.18	122.37	156.08	98.56
-march=i386 to k8	6.02	0.00	2.53	3.17	13.31	1.54	-0.65	1.49	-3.05	2.11	2.41
-fbranch-probabilities	3.49	0.39	4.74	4.28	0.72	1.81	-1.42	7.93	-2.16	0.20	1.66
-fguess-branch...
-fomit-frame-pointer	-0.14	0.12	3.49	2.25	9.32	1.02	0.38	0.29	0.00	1.03	1.63
-march=ppro to k8	8.34	0.00	0.00	-0.82	10.41	-1.50	0.26	-0.59	-0.94	-0.62	1.10
-fstrength-reduce	10.13	-0.26	1.46	1.03	-8.02	-1.54	0.13	0.89	-0.32	3.64	0.91
-funroll-loops	3.93	0.00	0.00	0.61	-7.65	1.81	0.52	4.62	0.95	-0.21	0.36
-fstrict-aliasing	0.00	0.00	0.00	0.00	0.00	-1.27	-0.13	0.14	0.00	0.00	0.00
-frename-registers	0.81	0.12	-0.62	0.00	-5.69	-0.52	1.98	-0.15	0.63	0.62	-0.19
-funit-at-a-time	0.13	0.00	0.00	0.00	-5.75	0.25	2.25	0.29	0.00	0.00	-0.19
-ftracer	1.65	0.00	0.00	0.00	-6.54	0.51	0.39	2.26	-0.32	-0.82	-0.37
-finline-functions	0.00	0.00	0.00	0.00	-7.14	3.70	1.85	-0.15	0.00	-0.21	-0.37
-maccumulate-	2.20	0.00	0.20	0.20	-6.37	-0.76	-0.40	0.00	0.00	0.41	-0.37
outgoing-args
-foptimize	-0.27	0.00	0.00	0.00	-6.44	2.84	0.00	0.14	-0.32	0.00	-0.37
sibling-calls
-fschedule-insns2	-0.54	0.13	1.04	2.72	-6.49	-0.26	-1.67	1.34	-6.48	1.04	-0.72
-freorder-blocks	0.68	-0.13	0.20	0.00	-4.78	-1.52	-0.13	1.04	-1.55	-0.62	-0.73
-fbranch-probabilities	1.78	0.00	-0.21	-2.80	0.00	-2.53	0.26	-1.17	-0.63	-2.23	-0.91
-fgcse	2.21	-0.39	0.20	-2.40	-3.99	2.02	-0.13	-0.59	-10.68	0.20	-1.43
-mfpmath=sse	2.43	0.25	3.29	-0.21	12.53	97.20	-0.14	1.47	13.20	3.30	10.14
-ffast-math	1.21	0.25	0.00	2.04	3.13	-0.26	3.89	0.58	-0.95	3.09	1.44
-fpeel-loops	3.78	0.00	0.00	2.25	0.00	0.51	-0.26	0.00	0.00	0.00	0.54
-funroll-all-loops	0.00	0.12	0.00	0.00	0.00	-2.54	-0.26	0.14	0.00	0.00	-0.19
-fpic	-5.15	0.25	-3.72	3.46	-0.43	-1.31	-10.15	-2.36	-11.64	-1.45	-3.10

File size (relative increase of the size of stripped binaries in percents):

options	wupwise	swim	mgrid	applu	mesa	art	equake	ammp	sixtrack	apsi	total
aggressive optimization	-3.88	-1.94	-20.88	-25.85	-23.54	14.89	-16.01	-17.99	-17.79	-11.69	-18.60
-fbranch-probabilities	0.24	-2.71	0.69	-4.31	-14.27	-7.93	-4.87	-11.72	-4.35	-7.09	-7.78
-fstrict-aliasing	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00
-march=ppro to -march=k8	0.00	0.53	0.00	-4.45	1.81	0.77	0.10	0.41	-0.60	0.00	0.04
-funit-at-a-time	0.00	0.00	0.00	0.00	0.24	0.00	3.26	0.43	0.00	0.00	0.14
-freorder-blocks	0.00	0.00	0.00	0.04	0.15	-0.12	0.43	0.31	0.28	0.00	0.20
-foptimize	0.00	0.00	0.00	0.00	0.26	0.00	0.00	0.02	0.23	1.56	0.30
sibling-calls
-frename-registers	0.00	0.26	0.00	0.04	0.25	0.33	0.65	0.02	0.61	0.00	0.38
-ftracer	7.98	0.00	0.00	0.00	0.07	0.44	0.76	5.35	0.00	1.44	0.66
-funroll-loops	5.15	6.26	0.00	1.15	0.06	7.76	1.21	0.43	0.07	2.48	0.57
-fgcse	-1.84	3.89	0.00	-4.45	-0.79	0.11	0.54	0.09	2.85	-3.17	0.76
-fbranch-probabilities	10.49	6.75	0.69	1.60	-0.55	11.19	2.58	7.22	0.63	3.16	1.38
-fguess-branch...
-fschedule-insns2	0.00	0.81	0.00	1.44	0.63	0.66	1.32	3.68	2.53	2.07	1.90
-fomit-frame-pointer	2.10	1.60	0.00	4.64	2.24	0.00	0.54	4.52	1.22	9.28	2.41
-fstrength-reduce	0.00	-1.33	0.00	31.50	-0.04	-2.69	-0.22	-0.54	4.37	3.07	3.14
-finline-functions	0.00	0.00	0.00	0.00	6.28	13.54	6.74	1.95	1.85	3.97	3.23
-march=i386 to -march=k8	7.17	-4.61	0.00	1.44	6.05	0.55	0.87	-0.68	4.19	8.23	4.35
-maccumulate-	7.52	1.91	0.00	0.71	3.53	1.23	1.77	0.43	6.49	9.36	5.03
outgoing-args
-ffast-math	0.00	-0.81	0.00	0.23	-1.37	-31.41	-31.50	-6.71	-0.07	-0.78	-1.89
-funroll-all-loops	0.00	0.00	0.00	0.00	0.00	0.11	0.65	0.00	0.00	0.00	0.01
-fpeel-loops	0.77	0.00	0.00	0.42	0.00	0.22	1.19	0.00	0.06	0.00	0.08
-fpic	4.90	-6.17	0.00	-25.58	9.63	-3.10	2.72	5.98	7.44	-0.10	5.74
-mfpmath=sse	4.04	7.23	0.00	10.72	2.53	7.29	8.28	15.12	8.83	6.81	7.33

Performance (relative speedups in percents):

Table: 64-bit SPECint 2000 with Aggressive Optimization (DEC Alpha EV56/600Mhz)

options	gzip	vpr	gcc	mcf	crafty	parser	eon	perl	gap	vortex	bzip2	twolf	avg
	0.00	-0.66	0.71	0.00	1.63	0.00	0.60	0.00	8.02	5.84	-0.55	4.72	1.96
aggressive optimization	143.98	77.03	73.26	16.94	105.84	141.75	505.83	119.81	128.84	94.27	180.89	71.33	115.27
-fschedule-insns2	16.23	10.00	1.51	2.20	11.18	2.75	20.56	8.84	2.87	3.78	15.38	5.63	8.08
-fschedule-insns
-funit-at-a-time	1.42	2.63	3.73	3.67	-2.83	28.33	18.57	16.66	0.00	16.42	3.52	5.51	7.63
-finline-functions	5.18	2.63	2.18	1.47	14.63	31.62	1.19	8.33	0.00	22.13	4.73	2.70	6.84
-fbranch-probabilities	1.45	7.58	6.06	2.22	15.47	27.50	5.03	14.00	2.08	-3.48	0.00	0.65	6.16
-fguess-branch...
-fbranch-probabilities	9.30	2.66	6.81	5.97	-4.33	29.66	-1.18	9.93	4.22	17.51	2.31	-0.66	5.44
-fschedule-insns2	7.87	6.16	3.75	0.72	7.69	-0.89	7.84	7.38	1.42	3.14	7.89	5.63	5.03
-fomit-frame-pointer	0.00	0.00	2.94	0.00	5.34	2.01	5.76	7.69	3.52	3.18	5.26	1.33	2.63
-freorder-blocks	0.71	0.00	2.15	0.00	14.10	1.31	-6.94	5.62	3.52	4.48	2.22	2.64	2.63
-fgcse	5.42	0.00	1.41	0.72	-1.02	-0.65	14.86	1.19	2.09	2.54	2.82	-0.66	1.94
-fif-conversion	2.96	5.47	0.00	2.20	4.97	0.65	13.15	0.00	2.08	3.20	-0.56	1.31	2.61
-fstrength-reduce	-3.53	-1.28	1.44	2.18	-3.30	-0.65	22.30	-2.96	2.08	-1.87	2.27	4.08	1.97
-funroll-loops	-1.42	0.00	2.18	0.00	22.29	0.00	3.65	-0.60	-1.37	1.87	0.00	-3.88	1.30
-fstrict-aliasing	-2.88	4.08	-0.71	0.73	2.13	8.45	-16.97	4.34	4.25	3.16	4.59	0.65	0.65
-frename-registers	0.71	0.64	0.71	-0.72	5.40	0.66	5.73	2.40	0.68	-12.50	-1.11	3.44	0.65
-foptimize	-2.12	0.00	0.71	-1.42	-14.80	-0.65	2.42	-2.49	0.68	1.86	1.11	-0.65	-1.28
sibling-calls
-ftracer	0.00	-4.55	0.00	-2.16	-12.07	-0.65	3.06	-2.95	0.00	1.25	1.11	-7.10	-2.59
-ffast-math	-1.44	-3.73	-2.12	2.18	7.65	0.00	-1.78	-0.59	1.37	8.60	-0.55	1.32	1.29
-funroll-all-loops	0.70	-0.65	-2.78	0.72	2.59	1.30	5.16	4.40	0.00	-3.04	0.55	-3.25	0.00
-fpeel-loops	0.00	3.28	-0.71	-1.43	4.44	1.30	-3.51	-2.36	0.00	0.61	0.00	-1.30	0.00
-fold-unroll-loops	0.00	0.64	0.00	0.72	-4.62	1.31	10.71	3.03	-1.37	-2.54	-6.63	0.00	0.00
-fpic	0.00	-2.64	0.00	0.73	-13.23	3.63	-4.10	-0.65	-1.40	-3.71	5.48	-2.65	-2.05

File size (relative increase of the size of stripped binaries in percents):

options	gzip	vpr	gcc	mcf	crafty	parser	eon	perl	gap	vortex	bzip2	twolf	total
aggressive optimization	-38.22	-29.20	-9.28	-42.75	-28.90	5.66	-49.91	-12.38	-36.23	-17.64	-3.00	-39.40	-22.85
-fbranch-probabilities	-10.66	-1.50	-2.43	0.79	-0.71	2.11	-4.12	-6.17	0.00	-3.29	-9.80	-5.73	-3.09
-fomit-frame-pointer	-10.98	-3.61	-1.53	0.00	-1.19	-3.23	-7.01	-2.35	-2.88	-2.10	-1.09	-3.01	-2.64
-fgcse	-0.25	-1.53	-1.07	0.00	-0.87	-1.56	-1.29	-0.48	0.08	0.01	-10.13	0.00	-0.84
-fstrict-aliasing	0.03	-1.22	0.00	0.00	-0.07	-0.28	0.26	-0.20	-0.53	-0.26	0.00	-3.01	-0.28
-freorder-blocks	-0.04	0.01	0.31	0.00	-0.43	0.01	-1.35	-0.23	-0.27	0.00	0.00	0.00	-0.09
-foptimize	0.06	-0.01	0.23	0.00	0.00	0.01	-1.26	-0.04	0.10	0.00	0.00	0.00	-0.02
sibling-calls
-frename-registers	0.06	-0.09	0.00	0.00	-0.10	0.02	0.08	-0.09	0.01	-0.03	0.00	0.00	-0.02
-fif-conversion	-0.10	-0.19	0.28	0.00	0.15	-0.21	-1.31	0.05	0.04	0.00	0.00	0.00	-0.01
-fstrength-reduce	0.06	0.33	0.00	0.00	0.23	-0.48	0.05	0.06	0.20	0.01	0.01	0.00	0.04
-funroll-loops	0.06	0.00	0.27	0.00	0.12	0.34	0.00	0.05	0.00	0.00	0.00	0.00	0.12
-ftracer	0.04	0.63	2.22	0.00	3.66	5.31	0.11	2.09	-0.11	3.25	0.00	3.19	1.99
-funit-at-a-time	-20.22	0.29	9.22	0.83	1.09	6.54	-4.12	4.22	0.00	-1.08	0.30	-2.99	3.12
-fbranch-probabilities	0.46	4.61	5.48	0.79	5.40	6.52	0.20	4.37	0.06	4.34	0.42	3.34	3.90
-fguess-branch...
-fschedule-insns2	0.00	4.24	4.73	0.00	3.87	0.00	5.63	3.53	4.29	3.47	0.00	3.41	4.06
-fschedule-insns2	0.00	4.42	5.01	0.00	3.87	0.00	7.14	4.76	5.25	4.69	0.00	3.41	4.76
-fschedule-insns
-finline-functions	0.47	8.20	23.93	0.79	3.89	43.62	-4.17	14.35	0.00	2.22	52.11	-2.89	11.68
-ffast-math	-0.31	-0.09	-0.01	-0.40	-0.06	-0.12	-0.04	-0.01	-0.07	-0.04	-0.12	-0.03	-0.04
-funroll-all-loops	0.99	0.31	0.00	0.00	0.43	2.29	0.00	0.11	0.00	0.02	0.00	0.00	0.13
-fpeel-loops	12.32	0.57	0.03	0.00	2.11	6.22	0.00	0.18	0.00	0.04	0.22	0.00	0.49
-fpic	-1.53	1.09	0.12	0.39	1.78	5.18	2.52	1.25	1.35	0.21	1.28	0.80	0.92
-fold-unroll-loops	12.39	8.85	-1.48	0.00	5.54	5.61	2.90	2.75	13.59	0.00	11.26	9.30	2.83

Performance (relative speedups in percents):

Table: 64-bit SPECfp 2000 with Aggressive Optimization (DEC Alpha EV56/600Mhz)

options	wupwise	swim	mgrid	applu	mesa	art	equake	ammp	apsi	avg
	0.00	-0.75	-0.21	0.00	0.93	0.00	0.83	-0.84	-1.76	0.00
-fschedule-insns2	14.49	10.74	50.22	17.06	28.57	7.60	17.08	24.61	25.41	21.69
-fschedule-insns
-fschedule-insns2	1.93	0.00	0.92	3.25	34.50	7.73	4.67	5.26	0.00	5.78
-fstrength-reduce	9.27	0.75	2.71	4.88	2.85	1.19	2.56	0.84	1.81	3.17
-fbranch-probabilities	3.12	0.00	1.44	1.33	14.21	7.10	3.41	-0.83	0.90	3.14
-fguess-branch...
-ftracer	1.85	0.00	1.02	0.20	8.54	1.14	0.82	0.84	6.79	2.36
-fbranch-probabilities	1.85	-0.75	-1.83	0.40	5.85	1.65	8.03	1.69	-1.74	1.56
-funit-at-a-time	2.48	0.74	-0.21	0.40	7.25	-1.68	10.00	2.56	-3.45	1.56
-fstrict-aliasing	0.00	0.00	-0.21	0.00	2.35	-6.56	9.00	0.84	0.90	0.77
-fomit-frame-pointer	2.48	-0.75	-0.41	0.00	4.34	-0.58	6.19	0.00	-0.88	0.77
-fgcse	0.60	0.00	0.00	-2.18	3.33	6.50	6.14	0.84	-2.61	0.76
-finline-functions	1.85	-0.75	-0.31	0.20	7.42	-9.40	2.56	0.84	-2.59	0.00
-freorder-blocks	0.00	-0.75	0.00	0.10	4.32	-5.24	6.14	-1.64	0.00	0.00
-frename-registers	0.60	-1.49	0.40	0.40	5.85	-1.66	0.82	0.84	-1.79	0.00
-foptimize	-0.61	0.00	-1.42	0.10	2.35	-4.66	5.21	0.00	-1.76	0.00
sibling-calls
-fif-conversion	0.00	0.00	0.20	0.20	0.94	1.10	4.31	-0.84	-0.90	0.00
-funroll-loops	0.60	-2.99	-1.01	0.10	1.87	-3.98	0.83	0.00	-0.88	-0.77
-fold-unroll-loops	6.66	-0.75	0.20	2.43	-36.75	3.48	-4.96	1.66	3.63	-3.08
-ffast-math	-0.60	0.00	0.10	0.30	-0.47	2.90	-5.47	-0.83	-2.59	-0.76
-fpic	0.63	0.00	-0.21	0.20	-2.04	2.95	0.00	0.00	0.87	0.00
-funroll-all-loops	0.00	-0.75	0.71	0.70	0.00	7.55	-0.82	-4.17	-1.79	0.00
-fpeel-loops	3.63	0.00	0.20	6.06	0.00	4.06	-4.14	0.00	0.00	0.76

File size (relative increase of the size of stripped binaries in percents):

options	wupwise	swim	mgrid	applu	mesa	art	equake	ammp	apsi	total
-fbranch-probabilities	0.37	-0.11	0.20	0.15	-7.43	-6.42	-0.06	-0.92	-2.47	-4.77
-funit-at-a-time	0.37	-0.11	0.20	0.15	-7.37	-6.42	0.57	0.03	-2.47	-4.61
-fomit-frame-pointer	0.00	-0.53	-1.53	-0.35	-3.45	-7.19	-2.12	-4.38	-1.30	-2.96
-fgcse	0.00	-26.92	0.57	-8.87	-1.06	-7.19	0.25	-0.02	-0.74	-1.93
-fstrict-aliasing	0.00	0.00	0.00	0.00	-0.31	-7.19	-2.17	-0.10	-0.15	-0.44
-fif-conversion	0.00	-0.21	-0.09	-0.08	-0.22	-0.73	0.05	0.31	-0.03	-0.11
-foptimize	0.00	0.00	0.00	0.00	-0.04	0.00	-0.06	-0.01	0.00	-0.02
sibling-calls
-freorder-blocks	0.00	0.10	0.00	0.02	0.28	-0.19	0.11	-0.43	-0.20	0.07
-funroll-loops	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.02	0.02	0.00
-frename-registers	0.00	0.10	0.16	-0.08	0.13	0.18	0.22	0.11	-0.32	0.05
-finline-functions	0.37	0.20	0.28	0.13	-0.74	19.29	8.46	1.21	-1.87	0.09
-ftracer	8.22	0.00	0.08	0.02	0.22	0.55	0.22	1.01	1.72	0.79
-fbranch-probabilities	9.36	0.84	1.36	-1.20	0.00	2.79	0.97	4.33	1.80	1.17
-fguess-branch...
-fstrength-reduce	7.50	2.68	3.28	7.17	-0.17	0.00	0.22	0.37	7.24	1.70
-fschedule-insns2	3.87	2.47	3.73	6.90	5.47	3.11	4.91	5.97	6.53	5.64
-fschedule-insns2	3.78	2.47	4.26	11.04	5.55	3.11	5.66	5.97	6.97	6.25
-fschedule-insns
-fpic	-1.98	-0.42	0.24	-2.57	-0.09	2.76	1.10	-1.06	-0.08	-3.83
-ffast-math	-0.21	-2.00	-1.05	-0.97	0.27	0.30	-0.60	-0.76	-0.61	-0.17
-fpeel-loops	0.00	0.00	0.00	0.90	0.00	7.73	2.60	0.00	0.00	0.30
-funroll-all-loops	0.00	0.00	0.81	0.29	0.00	7.73	1.13	0.37	0.27	0.34
-fold-unroll-loops	2.71	36.40	15.56	5.15	4.52	23.73	6.75	15.75	8.91	7.79

Real World Performance

One of the main goals has been to develop system ready for both enterprise and desktop (workstation) use. While the need of 64-bit addressing space for the enterprise is well understood, the effect on desktop performance is often discussed. The main drawback of 64-bit system, as discussed in section 2.1 is the increased memory footprint of the programs and subsequent slowdown of program startup times critical for today desktop systems.

In this section we present few simple benchmarks of this phenomenon on SuSE Linux 8.2. Both the 32-bit and 64-bit version of the system were installed on the equally sized ReiserFS partitions in the default configuration. The tests were performed in the same order on both systems with reboots in between. Additional packages were installed as needed. We hope this procedure to minimize amount of the noise in the numbers.

Table: Desktop Performance Relative to 32-bit System

test	speedup
bootup time	-0.9%
KDE startup from disk	18.1%
KDE startup from cache	14.6%

The Table compares startup times of several programs. As can be seen, the 64-bit system, perhaps surprisingly, is significantly faster in two of them and comparable in bootup times. The Table compares compilation of the package gimp.

Table: Gimp Compilation Times Relative to 32-bit System

		speedup
test	real	user	system
tar xjf	17.7%	9.8%	4%
./configure	-4.3%	0.7%	-31%
make	12.9%	19.8%	-39%

As can be seen on Table the memory consumption grows up by about 1/4 as expected, but due to relative compactness of CISC AMD64 instruction set, the increase is much smaller than one seen after switching to RISC or VLIW systems.

Table: Memory Resources Consumption

test	32-bit	64-bit	increase
konqueror	14 M	18 M	28%
gimp	8.6 M	9.9 M	15%
mozilla	22 M	27 M	22%

In fact Tables and shows decrease in the code section sizes.

Table: Size of Common Binaries in /usr/bin

section	32-bit	64-bit	increase
.text	56216 K	53419 K	-5%
.bss	18169 K	21098 K	16%
.data	10239 K	14076 K	37%
.rodata	17543 K	19734 K	12%
.eh_frame	546 K	8269 K	1414%
.rela.plt	358 K	1076 K	200%
.rela.dyn	40 K	126 K	215%
total	80435 K	91141 K	13%

Table: Size of Common Shared Libraries

section	32-bit	64-bit	increase
.text	71967 K	67526 K	-7%
.bss	33463 K	11557 K	-72%
.dynstr	13608 K	13587 K	-1%
.rodata	12119 K	12217 K	0%
.dynsym	11424 K	7611 K	66%
.eh_frame	6367 K	12730 K	99%
.data	6018 K	9695 K	61%
.rela.dyn	4382 K	12844 K	193%
.plt	3898 K	6499 K	66%
.rela.plt	1293 K	3888 K	200%
.got	823 K	1654 K	100%
total	171812 K	198111 K	15%

The major growths can be seen in the section .eh_frame that is usually not load into the memory and sections related to the dynamic relocations. According to our benchmarks these are not critical, since dynamic loader is still slightly faster in 64-bit version compared to 32-bit.

Overall, we can recommend use of 64-bit system instead of 32-bit on AMD64 machines intended for desktop use as long as memory consumption increased by 25% is not major limitation (that is hardly the case for computers sold today).