Date: Tue, 16 Dec 2008 09:16:52 -0700 From: Scott Long <scottl@samsco.org> To: Alexander Motin <mav@FreeBSD.org> Cc: svn-src-head@FreeBSD.org, svn-src-all@FreeBSD.org, src-committers@FreeBSD.org Subject: Re: svn commit: r186182 - head/sys/dev/ata Message-ID: <4947D474.9040802@samsco.org> In-Reply-To: <200812161604.mBGG4fBd041647@svn.freebsd.org> References: <200812161604.mBGG4fBd041647@svn.freebsd.org>
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Alexander Motin wrote: > Author: mav > Date: Tue Dec 16 16:04:40 2008 > New Revision: 186182 > URL: http://svn.freebsd.org/changeset/base/186182 > > Log: > Call ata_legacy() only once on attach and save it's result. Scanning PCI > configuration registers (which are not going to change) on every interrupt > looks expensive, especially when interrupt is shared. Profiling shows me 3% > of time spent by atapci0 on pure network load due to IRQ sharing with em0. > Nice change. PCI Config registers are exceptionally slow to access on most systems. Scott
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