Date: Wed, 25 Jan 2012 23:14:53 +0100 From: Florian Smeets <flo@FreeBSD.org> To: Andriy Gapon <avg@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: <4F207EDD.1000407@FreeBSD.org> In-Reply-To: <4F207B55.4020500@FreeBSD.org> References: <201112112102.pBBL21kB068967@svn.freebsd.org> <4F1DE4FF.3080606@FreeBSD.org> <4F207B55.4020500@FreeBSD.org>
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This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enigF63A6A7E0C371786D9BE842D Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On 25.01.12 22:59, Andriy Gapon wrote: > 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 i= n >>> SMP case >>> >=20 >> Hi, >=20 >> Attilio asked me to verify that this commit does not introduce a=20 >> performance regression. >=20 > First of all, thank you very much for doing this! >=20 >> The box used to run these tests was a 40 Core 32GB Xeon box (HTT was t= urned >> 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 lo= t of >> scaling work in 9.2 which improved the numbers quite a lot vs. 9.1. Th= e >> 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= =2E >=20 [mangled ministat removed] >=20 >> At 40 threads the results varied between 43000 - 76500 across reboots.= =20 >> Attilio suspects that this can be caused by the kernel memory layout=20 >> changing under the woods creating cache effects difficult to control, = >> therefor the scaling factor was reduced to 10 (~150MB work set) and th= e=20 >> numbers got deterministic across reboot. >=20 [mangled ministat removed] >=20 >=20 > Is it possible to see ministat's report for the difference between > 228424-40-sf10 and 228424-40-sf10-cl datasets? >=20 Sure, here we go. x 228424-40-sf10 + 228424-40-sf10-cl +----------------------------------------------------------------------+ |x + + + x ++x + x + + ++ x x x| | |____________________M_A_____________________| | | |______________A__M__________| | +----------------------------------------------------------------------+ N Min Max Median Avg Stdd= ev x 10 194093.35 198864.83 196129.36 196214.69 1545.87= 83 + 10 194288.28 197083.85 195955.26 195733.15 1012.35= 29 No difference proven at 95.0% confidence >> The 228424-40-sf10-cl results are with a patch from Attilio [1] which = he=20 >> will followup on. >=20 > I like the patch already, regardless of how much performance difference= it > produces :-) >=20 Florian [1] http://people.freebsd.org/~attilio/cachelineunshare.patch --------------enigF63A6A7E0C371786D9BE842D Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iEYEARECAAYFAk8gft4ACgkQapo8P8lCvwnSvACghSPbOTJMy4j/4pCGtP/+ZXn8 oOkAn3GQd9LA3SznCIMd1IE57PuQvwtv =hrC0 -----END PGP SIGNATURE----- --------------enigF63A6A7E0C371786D9BE842D--
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