Date: Tue, 22 Jun 2021 12:29:29 +0300 From: Dmitry Chagin <dchagin@freebsd.org> To: Dimitry Andric <dim@freebsd.org> Cc: src-committers@freebsd.org, dev-commits-src-all@freebsd.org, dev-commits-src-main@freebsd.org Subject: Re: git: 23408297fbf3 - main - Merge llvm-project 12.0.1 rc2 Message-ID: <YNGteaWBE/rTEMMK@heemeyer.club> In-Reply-To: <2A6DC940-653A-4B96-8103-DC3DE3F134AD@FreeBSD.org> References: <202106191811.15JIB4nu002236@gitrepo.freebsd.org> <YM85dZZktQApxHXl@heemeyer.club> <2A6DC940-653A-4B96-8103-DC3DE3F134AD@FreeBSD.org>
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On Sun, Jun 20, 2021 at 09:46:32PM +0200, Dimitry Andric wrote: > On 20 Jun 2021, at 14:49, Dmitry Chagin <dchagin@freebsd.org> wrote: > > > > On Sat, Jun 19, 2021 at 06:11:04PM +0000, Dimitry Andric wrote: > >> The branch main has been updated by dim: > >> > >> URL: https://cgit.FreeBSD.org/src/commit/?id=23408297fbf3089f0388a8873b02fa75ab3f5bb9 > >> > >> commit 23408297fbf3089f0388a8873b02fa75ab3f5bb9 > >> Merge: cac129e60300 e4bbddaec868 > >> Author: Dimitry Andric <dim@FreeBSD.org> > >> AuthorDate: 2021-06-19 10:06:00 +0000 > >> Commit: Dimitry Andric <dim@FreeBSD.org> > >> CommitDate: 2021-06-19 18:09:28 +0000 > >> > >> Merge llvm-project 12.0.1 rc2 > >> > >> This updates llvm, clang, compiler-rt, libc++, libunwind, lld, lldb and > >> openmp to llvmorg-12.0.1-rc2-0-ge7dac564cd0e, a.k.a. 12.0.1 rc2. > >> > >> PR: 255570 > >> MFC after: 6 weeks > >> > > hi! with 11 clang kernel build time is about 60 sec, with 12.0.0 and > > 12.0.1 rc2 build time increased to 500 sec. > > Did you previously have llvm/clang assertions turned off (via > MK_LLVM_ASSERTIONS=no)? > no, I found the reason. I tried to build a kernel without optimization, set CFLAGS=-O and forgot to remove it before building the world. > I did a few measurements of "make -j32 buildkernel", on > main-n247475-9d1cafb3049, with clang 11.0.1 and clang 12.0.1 (both with > assertions turned off, and statically linked: > > clang 11.0.1 (n=5): > > real user sys > 138.65 3145.23 285.25 > 129.00 3240.73 290.61 > 126.38 3244.03 284.76 > 128.90 3250.95 268.71 > 136.42 3250.73 267.93 > > clang 12.0.1 (n=5): > > real user sys > 129.16 3306.13 291.84 > 128.18 3308.14 284.32 > 128.77 3301.35 281.90 > 141.37 3293.22 282.20 > 129.93 3304.08 284.47 > > $ ministat -A clang1101-real.txt clang1201-real.txt > x clang1101-real.txt > + clang1201-real.txt > N Min Max Median Avg Stddev > x 5 126.38 138.65 129 131.87 5.3354662 > + 5 128.18 141.37 129.16 131.482 5.5639707 > No difference proven at 95.0% confidence > > $ ministat -A clang1101-user.txt clang1201-user.txt > x clang1101-user.txt > + clang1201-user.txt > N Min Max Median Avg Stddev > x 5 3145.23 3250.95 3244.03 3226.334 45.550423 > + 5 3293.22 3308.14 3304.08 3302.584 5.8070759 > Difference at 95.0% confidence > 76.25 +/- 47.3552 > 2.36336% +/- 1.50191% > (Student's t, pooled s = 32.4697) > > Before I merged 12.0.1, I did the same sort of measurement, but for > "make -j32 buildworld buildkernel" (with CROSS_TOOLCHAIN set so the > bootstrap compiler isn't built), and this showed roughly similar > results: > > $ ministat -A clang1101-real.txt clang1200-real.txt > x clang1101-real.txt > + clang1200-real.txt > N Min Max Median Avg Stddev > x 5 1410.24 1461.04 1434.2 1435.296 18.210247 > + 5 1461.54 1499.69 1462.07 1469.976 16.667199 > Difference at 95.0% confidence > 34.68 +/- 25.4583 > 2.41623% +/- 1.79718% > (Student's t, pooled s = 17.4558) > > $ ministat -A clang1101-user.txt clang1200-user.txt > x clang1101-user.txt > + clang1200-user.txt > N Min Max Median Avg Stddev > x 5 37495.09 37913.2 37750.64 37750.734 165.00886 > + 5 38133.12 38396.77 38390.77 38324.132 113.63363 > Difference at 95.0% confidence > 573.398 +/- 206.617 > 1.51891% +/- 0.552972% > (Student's t, pooled s = 141.67) > > So basically ~2% slower. It's would be a little tricky to find out if > there is any particular upstream commit that might be responsible, > as the difference is so small. > > I think I'll also compare the performance with assertions enabled, and > MK_SHARED_TOOLCHAIN=yes, which should be worse than the above, but still > comparable between 11.0 and 12.0. > > -Dimitry >
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