Date: Mon, 30 Apr 2007 22:10:33 +0100 (BST) From: Robert Watson <rwatson@FreeBSD.org> To: Dag-Erling =?iso-8859-1?Q?Sm=F8rgrav?= <des@des.no> Cc: current@freebsd.org, Hartmut Brandt <Hartmut.Brandt@dlr.de>, Tim Kientzle <kientzle@freebsd.org>, David G Lawrence <dg@dglawrence.com>, "Jesper B. Rosenkilde" <jbr@humppa.dk> Subject: Re: Suggestions on Avoiding syscall Overhead Message-ID: <20070430220936.W30345@fledge.watson.org> In-Reply-To: <86bqh5ppau.fsf@dwp.des.no> References: <f126fae00704221639l68095de1ye7ce9ba3d921bf20@mail.gmail.com> <20070423113400.GC28587@gw.humppa.dk> <462CD251.9060105@freebsd.org> <20070423161711.GV39474@elvis.mu.org> <462D821F.6030707@freebsd.org> <20070424042102.GI38475@tnn.dglawrence.com> <86veflholn.fsf@dwp.des.no> <20070428113752.A28395@fledge.watson.org> <4633299B.2020206@dlr.de> <20070428121554.T28395@fledge.watson.org> <86bqh5ppau.fsf@dwp.des.no>
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This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --0-1592702062-1177967433=:30345 Content-Type: TEXT/PLAIN; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE On Mon, 30 Apr 2007, Dag-Erling Sm=F8rgrav wrote: > Robert Watson <rwatson@FreeBSD.org> writes: > >> Unfortunately, this sort of thing can't be expressed using the standard= =20 >> APIs. This leaves us two choices: allow the behavior of standard APIs to= be=20 >> configured at some granularity, or introduce new APIs. My feeling is we= =20 >> should prefer new APIs, and suggest that programmers use those. Take a= =20 >> look at sys/sys/time.h:1.71 for an example of what might make sense. > > I'm not sure this is a good example. > > There is already a suitable extensible API: clock_gettime(), which is par= t=20 > of SUSv3. Define new CLOCK_* constants for requesting a faster, less=20 > precise timecounter, and if you feel like it, submit it to X/Open for=20 > inclusion in the next version of the SUS. You didn't look at that CVS revision, did you? The contrast being drawn here is between extending the API (that includes= =20 constants) and doing something like having environmental variables or other= =20 stuff change the definition of existing APIs (CLOCK_REALTIME, gettimeofday(= ),=20 etc). Robert N M Watson Computer Laboratory University of Cambridge --0-1592702062-1177967433=:30345--
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