Date: Fri, 12 Mar 2010 12:03:44 -0500 From: John Baldwin <john@baldwin.cx> To: Juli Mallett <jmallett@freebsd.org> Cc: src-committers@freebsd.org, svn-src-user@freebsd.org Subject: Re: svn commit: r205025 - user/jmallett/octeon/sys/mips/mips Message-ID: <201003121203.44340.john@baldwin.cx> In-Reply-To: <201003112032.o2BKWTrG089154@svn.freebsd.org> References: <201003112032.o2BKWTrG089154@svn.freebsd.org>
next in thread | previous in thread | raw e-mail | index | archive | help
On Thursday 11 March 2010 03:32:29 pm Juli Mallett wrote: > Author: jmallett > Date: Thu Mar 11 20:32:28 2010 > New Revision: 205025 > URL: http://svn.freebsd.org/changeset/base/205025 > > Log: > I don't know that a critical section is required here, but if it is we > really don't want to get interrupted between reading the counter and > calculating the ticks. In practice I think cputicks are only queried while holding a spin lock (so interrupts are disabled). Part of the comment before this is wrong as the cputicks are completely divorced from the timecounter code, so the tc code handling wrapping doesn't help any. However, if there is a way to use a single instruction to read all 64-bits of the ticker on mips64, it would probably be best to add a mips64-specific ticker method and use that for set_cputicker() instead of this one. -- John Baldwin
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?201003121203.44340.john>