Date: Wed, 31 Oct 2012 12:26:04 -0600 From: Ian Lepore <freebsd@damnhippie.dyndns.org> To: attilio@freebsd.org Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r242402 - in head/sys: kern vm Message-ID: <1351707964.1120.97.camel@revolution.hippie.lan> In-Reply-To: <CAJ-FndDRkBS57e9mzZoJWX5ugJ0KBGxhMSO50KB8Wm8MFudjCA@mail.gmail.com> References: <201210311807.q9VI7IcX000993@svn.freebsd.org> <CAJ-FndDRkBS57e9mzZoJWX5ugJ0KBGxhMSO50KB8Wm8MFudjCA@mail.gmail.com>
next in thread | previous in thread | raw e-mail | index | archive | help
On Wed, 2012-10-31 at 18:10 +0000, Attilio Rao wrote: > On Wed, Oct 31, 2012 at 6:07 PM, Attilio Rao <attilio@freebsd.org> wrote: > > Author: attilio > > Date: Wed Oct 31 18:07:18 2012 > > New Revision: 242402 > > URL: http://svn.freebsd.org/changeset/base/242402 > > > > Log: > > Rework the known mutexes to benefit about staying on their own > > cache line in order to avoid manual frobbing but using > > struct mtx_padalign. > > Interested developers can now dig and look for other mutexes to > convert and just do it. > Please, however, try to enclose a description about the benchmark > which lead you believe the necessity to pad the mutex and possibly > some numbers, in particular when the lock belongs to structures or the > ABI itself. > > Next steps involve porting the same mtx(9) changes to rwlock(9) and > port pvh global pmap lock to rwlock_padalign. > > Thanks, > Attilio > > Doesn't this padding to cache line size only help x86 processors in an SMP kernel? I was expecting to see some #ifdef SMP so that we don't pay a big price for no gain in small-memory ARM systems and such. But maybe I'm misunderstanding the reason for the padding. -- Ian
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?1351707964.1120.97.camel>