> -----Original Message----- > From: boun...@canonical.com [mailto:boun...@canonical.com] On Behalf Of > Lukasz Zemczak > Sent: quinta-feira, 2 de março de 2017 10:31 > To: Gustavo Serra Scalet <gustavo.sca...@eldorado.org.br> > Subject: [Bug 1667407] Re: improve 2x-3x sha256sum performance on > ppc64le due to current gcc optimization bug > > Could we get the bug details updated to follow the SRU template?
Done > Also, checking the SRU upload, one thing I don't particularly like is > that the attached patch has no description. Yes, the change is self- > explanatory, but some context in patch descriptions is always welcome. > Won't block on that though as I see some of the existing patches in the > package have empty 'Description:' fields anyway... Then I'd add to Michael Stone's patch: diff --git i/Makefile.in w/Makefile.in index bdf9a43..7a43897 100644 --- i/Makefile.in +++ w/Makefile.in @@ -14434,6 +14434,13 @@ $(factor_tests): $(tf)/run.sh $(tf)/create-test.sh $(TEST_LOGS): $(PROGRAMS) +# REMOVE THIS HANDLING FOR PPC64 IF GCC > 7.0 IS USED +# Shutting off -fschedule-insns optimization due to huge performance drop +# (around 2 to 3 times). +ifeq ($(DEB_TARGET_ARCH), ppc64el) +lib/sha256.o: CFLAGS+=-fno-schedule-insns +endif + # Tell versions [3.59,3.63) of GNU make to not export all variables. # Otherwise a system limit (for SysV at least) may be exceeded. .NOEXPORT: -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to coreutils in Ubuntu. https://bugs.launchpad.net/bugs/1667407 Title: improve 2x-3x sha256sum performance on ppc64le due to current gcc optimization bug Status in coreutils package in Ubuntu: Fix Released Status in coreutils source package in Xenial: New Status in coreutils source package in Yakkety: New Status in coreutils package in Debian: Fix Released Bug description: [Impact] * Performance drop of 2x-3x on ppc64le when using sha256sum * Please backport this bug to last LTS as this application is widely used. * This fix is due to a optimization issue found on gcc v4.9 to gcc v7.0. [Test Case] * Run sha256sum with a big file and measure the time it takes. The patch improves this timing up to 3 times faster. [Regression Potential] * This patch is specifically for the sha256.o object, affecting only this binary. [Other Info] Michael Stone's improved patch: Index: coreutils-8.26/Makefile.in =================================================================== --- coreutils-8.26.orig/Makefile.in 2016-11-30 13:34:55.000000000 -0500 +++ coreutils-8.26/Makefile.in 2017-02-22 07:18:55.352394058 -0500 @@ -14661,6 +14661,10 @@ $(TEST_LOGS): $(PROGRAMS) +ifeq ($(DEB_TARGET_ARCH), ppc64el) +lib/sha256.o: CFLAGS+=-fno-schedule-insns +endif + # Tell versions [3.59,3.63) of GNU make to not export all variables. # Otherwise a system limit (for SysV at least) may be exceeded. .NOEXPORT: Original bug description: The sha256sum provided by coreutils (without openssl) is performing poorly with gcc versions >= 4.9 until 7.0 (currently under development). The reason for that is the -fschedule-insns optimization that is used with -O2. By simply deactivating it, there is a performance improvement of 2 to 3 times. I'm using Ubuntu 16.10 and the coreutils package version 8.25-2ubuntu2. Please check the following closed debian bug report: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=854053 Be aware of the following conditions that are required: * If ppc64le * If gcc being used is >= 4.9 and < 7.0 Notes: 1) gcc-7 is not affected by this bug (verified on 20170129 snapshot). 2) clang is not affected by this bug (verified on v3.8 and v3.9). 3) strangely the sha512 is not affected by this. Below a demonstration of how it performs on my POWER8 machine: =================================================== $ (./configure && make -j9) > /dev/null && time src/sha256sum ~/ubuntu-16.10-server-ppc64el.iso configure: WARNING: libacl development library was not found or not usable. configure: WARNING: GNU coreutils will be built without ACL support. configure: WARNING: libattr development library was not found or not usable. configure: WARNING: GNU coreutils will be built without xattr support. configure: WARNING: libcap library was not found or not usable. configure: WARNING: GNU coreutils will be built without capability support. configure: WARNING: libgmp development library was not found or not usable. configure: WARNING: GNU coreutils will be built without GMP support. src/who.c: In function 'print_user': src/who.c:454:20: warning: initialization discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers] int *a = utmp_ent->ut_addr_v6; ^~~~~~~~ d14bdb413ea6cdc8d9354fcbc37a834b7de0c23f992deb0c6764d0fd5d65408e /home/gut/ubuntu-16.10-server-ppc64el.iso real 0m18.670s user 0m16.566s sys 0m0.745s $ # now with the following patch: ## Check Michael Stone's patch for an improved version. $ diff Makefile.in ../Makefile.in 8989c8989 < @am__fastdepCC_TRUE@ $(COMPILE) -MT $@ -MD -MP -MF $$depbase.Tpo -c -o $@ $< &&\ --- > @am__fastdepCC_TRUE@ $(COMPILE) $$([ "$@" == "lib/sha256.o" ] && echo "-fno-schedule-insns") -MT $@ -MD -MP -MF $$depbase.Tpo -c -o $@ $< &&\ $ cp ../Makefile.in Makefile.in $ (./configure && make -j9) > /dev/null && time src/sha256sum ~/ubuntu-16.10-server-ppc64el.iso configure: WARNING: libacl development library was not found or not usable. configure: WARNING: GNU coreutils will be built without ACL support. configure: WARNING: libattr development library was not found or not usable. configure: WARNING: GNU coreutils will be built without xattr support. configure: WARNING: libcap library was not found or not usable. configure: WARNING: GNU coreutils will be built without capability support. configure: WARNING: libgmp development library was not found or not usable. configure: WARNING: GNU coreutils will be built without GMP support. src/who.c: In function 'print_user': src/who.c:454:20: warning: initialization discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers] int *a = utmp_ent->ut_addr_v6; ^~~~~~~~ d14bdb413ea6cdc8d9354fcbc37a834b7de0c23f992deb0c6764d0fd5d65408e /home/gut/ubuntu-16.10-server-ppc64el.iso real 0m5.903s user 0m5.560s sys 0m0.255s To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/coreutils/+bug/1667407/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
