On Fri, Oct 26, 2012 at 6:32 AM, Evgeny Voevodin <e.voevo...@samsung.com> wrote: > Today I made more precise testing with usage of --enable-profiler. > > Here is the test procedure: > 1. Boot Linux Kernel 5 times. > 2. For each iteration wait while "JIT cycles" is stable for ~10 seconds > 3. Write down the "cycles/op" > > Here are the results: > > Before clean-up: > min: 731.9 > max: 735.8 > avg: 734.3 > standard deviation: ~2 = 0.3% > Avarage cycles/op = 734 +- 2 > > After clean-up: > min: 747.2 > max: 751.7 > avg: 750.5 > standard deviation: ~2 = 0.3% > Avarage cycles/op = 750 +- 2 > Slow-down of TCG code generation = 2.2% > > > After clean-up with TCGContext *const tcg_cur_ctx: > min: 730.6 > max: 733.2 > avg: 728.7 > standard deviation: ~2 = 0.3% > Avarage cycles/op = 729 +- 2 > Slow-down of TCG code generation = 0% > > I suggest to define tcg_cur_ctx as TCGContext *const. > Then we will get rid of TCG code generation slow-down and also > will have no usage of global variables.
How does this compare with the original version without pointers? I think that version may be safer to be assumed to be optimized by the compiler. > > > On 10/25/2012 10:45 AM, Evgeny Voevodin wrote: >> >> Here are the results of tests before and after this patch series was >> applied: >> >> * EEMBC CoreMark (before -> after) >> - Guest: Exynos4210 ARMv7, Linux (Custom buildroot image) >> - Host: Intel(R) Core(TM) i5 CPU 750 @ 2.67GHz, 4GB RAM, Linux >> - Results: 1148.105626 -> 1161.440186 (+1.16%) >> >> * nbench (before -> after) >> - Guest: Exynos4210 ARMv7, Linux (Custom buildroot image) >> - Host: Intel(R) Core(TM) i5 CPU 750 @ 2.67GHz, 4GB RAM, Linux >> - Results >> . MEMORY INDEX: 1.864 -> 1.862 (-0.11%) >> . INTEGER INDEX: 2.518 -> 2.523 (+0.2%) >> . FLOATING-POINT INDEX: 0.385 -> 0.394 (+2.34%) >> >> >> Those tests show that it became even faster :)) >> >> But I'm quite sceptical about such results. >> The thing is that in case of nbench it prints the warning if results are >> not 95% statistically accurate. >> So we can be sure that nbench result is 95% accurate. >> And it's obvious that result shown above are in the scope of this >> accuracy. >> I don't know the accuracy of CoreMark. >> >> So, the main decision we can make that this patch series didn't >> introduce any slow-down comparable to inaccuracy of the measurement. >> >> Is this enough? >> >> On 10/23/2012 10:21 AM, Evgeny Voevodin wrote: >>> >>> This set of patches moves global variables to tcg_ctx: >>> gen_opc_ptr >>> gen_opparam_ptr >>> gen_opc_buf >>> gen_opparam_buf >>> >>> Build tested for all targets. >>> Execution tested on ARM. >>> >>> I didn't notice any slow-down of kernel boot after this set was applied. >>> >>> Changelog: >>> v1->v2: >>> Introduced TCGContext *tcg_cur_ctx global to use in those places where >>> we don't >>> have an interface to pass pointer to tcg_ctx. >>> Code style clean-up >>> >>> Evgeny (2): >>> tcg/tcg.h: Duplicate global TCG variables in TCGContext >>> TCG: Remove unused global variables >>> >>> Evgeny Voevodin (5): >>> translate-all.c: Introduce TCGContext *tcg_cur_ctx >>> TCG: Use gen_opc_ptr from context instead of global variable. >>> TCG: Use gen_opparam_ptr from context instead of global variable. >>> TCG: Use gen_opc_buf from context instead of global variable. >>> TCG: Use gen_opparam_buf from context instead of global variable. >>> >>> gen-icount.h | 2 +- >>> target-alpha/translate.c | 10 +- >>> target-arm/translate.c | 10 +- >>> target-cris/translate.c | 13 +- >>> target-i386/translate.c | 10 +- >>> target-lm32/translate.c | 13 +- >>> target-m68k/translate.c | 10 +- >>> target-microblaze/translate.c | 13 +- >>> target-mips/translate.c | 11 +- >>> target-openrisc/translate.c | 13 +- >>> target-ppc/translate.c | 11 +- >>> target-s390x/translate.c | 11 +- >>> target-sh4/translate.c | 10 +- >>> target-sparc/translate.c | 10 +- >>> target-unicore32/translate.c | 10 +- >>> target-xtensa/translate.c | 8 +- >>> tcg/optimize.c | 62 ++++---- >>> tcg/tcg-op.h | 324 >>> ++++++++++++++++++++--------------------- >>> tcg/tcg.c | 85 ++++++----- >>> tcg/tcg.h | 11 +- >>> translate-all.c | 4 +- >>> 21 files changed, 328 insertions(+), 323 deletions(-) >>> >> >> > > > -- > Kind regards, > Evgeny Voevodin, > Technical Leader, > Mobile Group, > Samsung Moscow Research Center, > e-mail: e.voevo...@samsung.com
