Date: Sun, 21 Jan 2007 23:35:45 +0100 From: Marius Nuennerich <marius.nuennerich@gmx.net> To: freebsd-arch@freebsd.org Subject: Re: bzero & bcopy alignment Message-ID: <20070121233545.2a8ce09a@sol.hackerzberg.local> In-Reply-To: <ep0p8i$86q$1@sea.gmane.org> References: <ep0mlv$194$1@sea.gmane.org> <20070121140019.A83688@xorpc.icir.org> <ep0p8i$86q$1@sea.gmane.org>
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On Sun, 21 Jan 2007 23:25:14 +0100 Ivan Voras <ivoras@fer.hr> wrote: > Luigi Rizzo wrote: > > On Sun, Jan 21, 2007 at 10:41:09PM +0100, Ivan Voras wrote: > >> Following recent discussion on alignment of bzero() and bcopy(), I've > >> added some statistics collecting code to bzero() and bcopy() for > >> practice (on a RELENG_6 box), and here are the cumulative results for > >> argument alignment: > > > > i think these profiles depend heavily on the hardware > > and usage patterns. > > Yes, I agree. For what it's worth, this was on vmware, almost no network > activity. > > > e.g. some network drivers force you to aligned buffers > > which results in misaligned payload requesting in > > turn an unaligned bcopy. Not that one can help with this, > > but i think that is also important to locate the locations > > in the source where the poorly aligned (1-2, maybe > > 4 and 8 to some degree) ops occur. > > Any magic tricks to identify the caller of "current" function in the kernel? I don't know if the dtrace port is ready for this, but afaik it would be easy with dtrace.
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