Date: Mon, 02 Feb 2015 00:53:57 +0000 From: Steven Hartland <steven@multiplay.co.uk> To: Davide Italiano <davide@freebsd.org> Cc: "svn-src-head@freebsd.org" <svn-src-head@freebsd.org>, "svn-src-all@freebsd.org" <svn-src-all@freebsd.org>, "src-committers@freebsd.org" <src-committers@freebsd.org> Subject: Re: svn commit: r278040 - head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs Message-ID: <54CECAA5.9090406@freebsd.org> In-Reply-To: <CACYV=-G-NeEAn1ewQowzX34PgA5tum8jG6-rdt%2BQPuo4-ytBqg@mail.gmail.com> References: <201502020017.t120Hb2g095087@svn.freebsd.org> <CACYV=-G-NeEAn1ewQowzX34PgA5tum8jG6-rdt%2BQPuo4-ytBqg@mail.gmail.com>
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On 02/02/2015 00:28, Davide Italiano wrote: > On Mon, Feb 2, 2015 at 1:17 AM, Steven Hartland <smh@freebsd.org> wrote: >> Author: smh >> Date: Mon Feb 2 00:17:36 2015 >> New Revision: 278040 >> URL: https://svnweb.freebsd.org/changeset/base/278040 >> >> Log: >> Prevent inlining txg_quiesce >> >> This allows dtrace to monitor the calls to txg_quiesce which can be really >> helpful. >> >> Also standardise __noinline order for arc_kmem_reap_now. >> >> Sponsored by: Multiplay >> >> > I found this while I was at iXsystems, trying to port Richard Elling's > arc statistics utility to FreeBSD. > I do not disagree with the change in theory, but I never committed > this because I was worried of performance penalty. > Last time I checked Solaris/Illumos actually do not inline this > function without any particular directive (I guess this is mostly due > to difference in toolchain, in particular in the compiler), so it > shouldn't be a big deal, but if you have time, do you mind to check > the penalty introduced, if any, is negligible? Performance difference should be negligible if not unmeasurable, but I'll run some tests to check call frequency to be sure. From what I can tell its inlined because there is only a single caller (txg_quiesce_thread). Regards Steve
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