On Wed, May 30, 2018 at 5:43 AM, H.J. Lu <hjl.to...@gmail.com> wrote: > On Sun, May 20, 2018 at 11:51 AM, Jan Hubicka <hubi...@ucw.cz> wrote: >>> r254152 disabled partial_reg_dependency and movx for Haswell and newer >>> Intel processors. r258972 restored them for skylake-avx512. For Haswell, >>> movx improves performance. But partial_reg_stall may be better than >>> partial_reg_dependency in theory. We will investigate performance impact >>> of partial_reg_stall vs partial_reg_dependency on Haswell for GCC 9. In >>> the meantime, this patch restores both partial_reg_dependency and mox for >>> Haswell in GCC 8. >>> >>> OK for GCC 8? >> >> I would still like to know in what situations/bechnarks it improves the >> performance. >> The change was benchmarked on spec2000/2006 plus some additional benchmarks >> and, so >> it would be nice to know where it hurts. > > From > > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85829#c5: > > I have made measurements on HSW comparing > -mtune-ctrl=movx,partial_reg_dependency -Ofast -march=haswell to > -Ofast -mtune=haswell and I see improvements on EEMBC benchmarks. > > automotive > ========= > aifftr01 (default) - goodperf: Runtime improvement of 2.6% (time). > aiifft01 (default) - goodperf: Runtime improvement of 2.2% (time). > > networking > ========= > ip_pktcheckb1m (default) - goodperf: Runtime improvement of 3.8% (time). > ip_pktcheckb2m (default) - goodperf: Runtime improvement of 5.2% (time). > ip_pktcheckb4m (default) - goodperf: Runtime improvement of 4.4% (time). > ip_pktcheckb512k (default) - goodperf: Runtime improvement of 4.2% (time). > > telecom > ========= > fft00data_1 (default) - goodperf: Runtime improvement of 8.4% (time). > fft00data_2 (default) - goodperf: Runtime improvement of 8.6% (time). > fft00data_3 (default) - goodperf: Runtime improvement of 9.0% (time). > > OK for GCC 8? >
This is the patch I am going to check into GCC 8. -- H.J.
From 9ecbfa1fd04dc4370a9ec4f3d56189cc07aee668 Mon Sep 17 00:00:00 2001 From: "H.J. Lu" <hjl.to...@gmail.com> Date: Thu, 17 May 2018 09:52:09 -0700 Subject: [PATCH] x86: Re-enable partial_reg_dependency and movx for Haswell r254152 disabled partial_reg_dependency and movx for Haswell and newer Intel processors. r258972 restored them for skylake-avx512. For Haswell, movx improves performance. But partial_reg_stall may be better than partial_reg_dependency in theory. We will investigate performance impact of partial_reg_stall vs partial_reg_dependency on Haswell for GCC 9. In the meantime, this patch restores both partial_reg_dependency and mox for Haswell in GCC 8. On Haswell, improvements for EEMBC benchmarks with -mtune-ctrl=movx,partial_reg_dependency -Ofast -march=haswell vs -Ofast -mtune=haswell are automotive ========= aifftr01 (default) - goodperf: Runtime improvement of 2.6% (time). aiifft01 (default) - goodperf: Runtime improvement of 2.2% (time). networking ========= ip_pktcheckb1m (default) - goodperf: Runtime improvement of 3.8% (time). ip_pktcheckb2m (default) - goodperf: Runtime improvement of 5.2% (time). ip_pktcheckb4m (default) - goodperf: Runtime improvement of 4.4% (time). ip_pktcheckb512k (default) - goodperf: Runtime improvement of 4.2% (time). telecom ========= fft00data_1 (default) - goodperf: Runtime improvement of 8.4% (time). fft00data_2 (default) - goodperf: Runtime improvement of 8.6% (time). fft00data_3 (default) - goodperf: Runtime improvement of 9.0% (time). PR target/85829 * config/i386/x86-tune.def: Re-enable partial_reg_dependency and movx for Haswell. --- gcc/config/i386/x86-tune.def | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/gcc/config/i386/x86-tune.def b/gcc/config/i386/x86-tune.def index 5649fdcf416..60625668236 100644 --- a/gcc/config/i386/x86-tune.def +++ b/gcc/config/i386/x86-tune.def @@ -48,7 +48,7 @@ DEF_TUNE (X86_TUNE_SCHEDULE, "schedule", over partial stores. For example preffer MOVZBL or MOVQ to load 8bit value over movb. */ DEF_TUNE (X86_TUNE_PARTIAL_REG_DEPENDENCY, "partial_reg_dependency", - m_P4_NOCONA | m_CORE2 | m_NEHALEM | m_SANDYBRIDGE + m_P4_NOCONA | m_CORE2 | m_NEHALEM | m_SANDYBRIDGE | m_HASWELL | m_BONNELL | m_SILVERMONT | m_INTEL | m_KNL | m_KNM | m_AMD_MULTIPLE | m_SKYLAKE_AVX512 | m_GENERIC) @@ -84,7 +84,7 @@ DEF_TUNE (X86_TUNE_PARTIAL_FLAG_REG_STALL, "partial_flag_reg_stall", partial dependencies. */ DEF_TUNE (X86_TUNE_MOVX, "movx", m_PPRO | m_P4_NOCONA | m_CORE2 | m_NEHALEM | m_SANDYBRIDGE - | m_BONNELL | m_SILVERMONT | m_KNL | m_KNM | m_INTEL + | m_BONNELL | m_SILVERMONT | m_KNL | m_KNM | m_INTEL | m_HASWELL | m_GEODE | m_AMD_MULTIPLE | m_SKYLAKE_AVX512 | m_GENERIC) /* X86_TUNE_MEMORY_MISMATCH_STALL: Avoid partial stores that are followed by -- 2.17.0