Date: Wed, 25 Jan 2012 23:59:49 +0200 From: Andriy Gapon <avg@FreeBSD.org> To: Florian Smeets <flo@FreeBSD.org> Cc: svn-src-head@FreeBSD.org, svn-src-all@FreeBSD.org, src-committers@FreeBSD.org Subject: Re: svn commit: r228424 - in head/sys: kern sys Message-ID: <4F207B55.4020500@FreeBSD.org> In-Reply-To: <4F1DE4FF.3080606@FreeBSD.org> References: <201112112102.pBBL21kB068967@svn.freebsd.org> <4F1DE4FF.3080606@FreeBSD.org>
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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 on 24/01/2012 00:53 Florian Smeets said the following: > On 11.12.11 22:02, Andriy Gapon wrote: >> Author: avg Date: Sun Dec 11 21:02:01 2011 New Revision: 228424 URL: >> http://svn.freebsd.org/changeset/base/228424 >> >> Log: panic: add a switch and infrastructure for stopping other CPUs in >> SMP case >> > > Hi, > > Attilio asked me to verify that this commit does not introduce a > performance regression. First of all, thank you very much for doing this! > The box used to run these tests was a 40 Core 32GB Xeon box (HTT was turned > off, so 40 real hardware cores). As benchmark pgbench/PostgreSQL were used, > a snapshot of PostgreSQL 9.2 from 16.01.2012 was used as they did a lot of > scaling work in 9.2 which improved the numbers quite a lot vs. 9.1. The > initial benchmarks were run with a scaling factor of 100 which creates a > database work set of ~1.5GB. Max throughput was achieved at 20 Clients. > > x 228423-20 + 228424-20 > +----------------------------------------------------------------------+ | > x + | |x x x > +* + + xxx * ++ + + x| | > |___________________A______M_____________| | | > |___________A____M_____| | > +----------------------------------------------------------------------+ N > Min Max Median Avg Stddev x 10 > 111073.26 115016.79 113113.49 112745.69 1169.2132 + 10 > 112583.56 114454.33 113668.08 113343.31 661.31761 No > difference proven at 95.0% confidence > > At 40 threads the results varied between 43000 - 76500 across reboots. > Attilio suspects that this can be caused by the kernel memory layout > changing under the woods creating cache effects difficult to control, > therefor the scaling factor was reduced to 10 (~150MB work set) and the > numbers got deterministic across reboot. > > x 228423-40-sf10 + 228424-40-sf10 * 228424-40-sf10-cl > +----------------------------------------------------------------------+ |x > x x *** * * + x **+ *+ * * ** + + +| | > |__________A__________| | | > |______________MA________________| | | > |__________A__M_______| | > +----------------------------------------------------------------------+ N > Min Max Median Avg Stddev x 10 > 192489.43 196045.39 194138.34 194149.19 986.61561 + 10 > 194093.35 198864.83 196129.36 196214.69 1545.8783 > Difference at 95.0% confidence 2065.5 +/- 1218.43 1.06387% +/- 0.627572% > (Student's t, pooled s = 1296.76) * 10 194288.28 197083.85 > 195955.26 195733.15 1012.3529 Difference at 95.0% confidence > 1583.96 +/- 939.189 0.815847% +/- 0.483746% (Student's t, pooled s = > 999.567) Is it possible to see ministat's report for the difference between 228424-40-sf10 and 228424-40-sf10-cl datasets? > The 228424-40-sf10-cl results are with a patch from Attilio [1] which he > will followup on. I like the patch already, regardless of how much performance difference it produces :-) > If anybody wants to look at the raw numbers they are available at [2]. > > There are results for pbzip2 runs here [3] also, the numbers are "real" > time from /usr/bin/time. > > Cheers, Florian > > [1] http://people.freebsd.org/~attilio/cachelineunshare.patch [2] > http://tb.smeets.im/~flo/stop-sched/pgsql/ [3] > http://tb.smeets.im/~flo/stop-sched/pbzip2/ > - -- Andriy Gapon -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.18 (FreeBSD) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iQEcBAEBAgAGBQJPIHtVAAoJEHSlLSemUf4vSTQIALerbsXk+V283mw9lk7T4Jbk QOYhyexcLz+GDs9X3B35LmP46romYTT21S2DgVDtK76pq2a1SBGhkhExWi9sfZdv RuTWOiInEd8d06I7T+SdCosDr6UGMNUMb+8h/pBOzyGEUt0WOugbqmJNPUu9uFEb KGrSnjr6xDIIY/bty01H4unnqfZX5t6RTMuxzrbxxSmf8SIjChQhDgFZpSq0ue4n QJjTg1DK0W6mHHTIzpfydya+I4uEQCkxQiElFNsJla7W3ZyAPgXlMVpYdmcxD+xr 2NUMOjXvQ2sWkVKaKDVqmlYxs5mtyBvjOR23cPuoP6rYNrtgtXLMiG/KAtaDuhs= =cI8w -----END PGP SIGNATURE-----
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