Date: Thu, 1 Sep 2011 16:11:55 +0200 From: Attilio Rao <attilio@freebsd.org> To: Sean Bruno <seanbru@yahoo-inc.com> Cc: "freebsd-hackers@freebsd.org" <freebsd-hackers@freebsd.org>, Ivan Voras <ivoras@freebsd.org> Subject: Re: Large machine test ideas Message-ID: <CAJ-FndCbXs0btQUc8_L3F4kcsdu5WN-75HY%2BhdKY%2B5OGhase2Q@mail.gmail.com> In-Reply-To: <1314818323.2610.6.camel@hitfishpass-lx.corp.yahoo.com> References: <j38lj5$s9a$1@dough.gmane.org> <CAMBSHm_Sv_KZUs4h-tDGAZCq8s2qo_bMmfZxLbVkcH1=_Wu0OQ@mail.gmail.com> <CAF-QHFW=aU3=iKE9WMg6%2BD6eP9OXth=c0AidBc140ykmAPD2zg@mail.gmail.com> <201108291415.32605.jhb@freebsd.org> <j3ju8s$kuo$2@dough.gmane.org> <1314818323.2610.6.camel@hitfishpass-lx.corp.yahoo.com>
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2011/8/31 Sean Bruno <seanbru@yahoo-inc.com>: > On Tue, 2011-08-30 at 17:11 -0700, Ivan Voras wrote: >> On 29.8.2011. 20:15, John Baldwin wrote: >> >> > However, the SRAT code just ignores the table when it encounters an is= sue like >> > this, it doesn't hang. =C2=A0Something else later in the boot must hav= e hung. >> >> Anyway... that machine can in its maximal configuration be populated >> with eight 10-core CPUs, i.e. 80 physical / 160 logical, so here's a >> vote from me to bump the shiny new cpuset infrastructure maximum CPU >> count to 256 before 9.0. >> >> http://www.supermicro.com/products/system/5U/5086/SYS-5086B-TRF.cfm > > Doesn't that (MAXCPU) seriously impact VM usage, lock contention > etc ... ? > > I mean, if we have 2 cpus in a machine, but MAXCPU is set to 256, there > is a bunch of "lost" memory and higher levels of lock contention? > > I thought that attilio was taking a stab at enhancing this, but at the > current time anything more than a value of 64 for MAXCPU is kind of a > "caveat emptor" area of FreeBSD. With newest current you can redefine MAXCPU in your kernel config, so you don't need to bump the default value. I think 64 as default value is good enough. Removing MAXCPU dependency from the KBI is an important project someone should adopt and bring to conclusion. Thanks, Attilio --=20 Peace can only be achieved by understanding - A. Einstein
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