Date: Sun, 13 Oct 2013 15:26:12 -0600 From: "Justin T. Gibbs" <gibbs@FreeBSD.org> To: Alexander Motin <mav@FreeBSD.org> Cc: svn-src-projects@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r256295 - in projects/camlock/sys: geom kern Message-ID: <2A8C3ACD-A37E-48CB-9103-DA359B3B0536@FreeBSD.org> In-Reply-To: <201310102003.r9AK3smQ038364@svn.freebsd.org> References: <201310102003.r9AK3smQ038364@svn.freebsd.org>
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On Oct 10, 2013, at 2:03 PM, Alexander Motin <mav@FreeBSD.org> wrote: > Author: mav > Date: Thu Oct 10 20:03:54 2013 > New Revision: 256295 > URL: http://svnweb.freebsd.org/changeset/base/256295 > > Log: > Use the same satistics for disk and its GEOM provider. > > Avoiding double accounting allows to reduce CPU load on I/O, especially on > machines with slow timecounter. As side effect it also makes gstat show > statistics for raw disk providers even when kern.geom.collectstats is set > to zero, making that mode more usable. … > Modified: projects/camlock/sys/geom/geom_io.c > ============================================================================== > --- projects/camlock/sys/geom/geom_io.c Thu Oct 10 19:56:31 2013 (r256294) > +++ projects/camlock/sys/geom/geom_io.c Thu Oct 10 20:03:54 2013 (r256295) > @@ -510,7 +510,7 @@ g_io_request(struct bio *bp, struct g_co > > KASSERT(!(bp->bio_flags & BIO_ONQUEUE), > ("Bio already on queue bp=%p", bp)); > - if (g_collectstats) > + if ((g_collectstats & ~(pp->stat ? 0 : 1)) != 0) > binuptime(&bp->bio_t0); > else > getbinuptime(&bp->bio_t0); This is pretty obscure and further compounds the original bug that there is no enum defining the bits in g_collectstats. Can you please: 1) Add an enum with constants for the two bits in g_collectstats with nice comments for what they do. 2) Use those constants everywhere and change your original logic to make it more readable? e.g. if ((g_collecstats & G_CONSUMER_STATS) != 0 || ((g_collecstats & G_PROVIDER_STATS) != 0 && pp->stat != NULL)) I would bet the compiler optimizes this just as well as your original logic. Thanks, Justinhelp
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