Date: Sat, 23 Jun 2001 13:14:11 -0500 (CDT) From: Mike Silbersack <silby@silby.com> To: Matt Dillon <dillon@earth.backplane.com> Cc: "Jonathan Lemon <jlemon@flugsvamp.com> Alfred Perlstein" <bright@sneakerz.org>, Mike Silbersack <silby@FreeBSD.ORG>, <cvs-committers@FreeBSD.ORG>, <cvs-all@FreeBSD.ORG>, <jlemon@FreeBSD.ORG>, <bmilekic@FreeBSD.ORG> Subject: Re: cvs commit: src/sys/netinet tcp_input.c tcp_output.c tcp_subr.c tcp_timer.c tcp_usrreq.c tcp_var.h Message-ID: <20010623131152.I23528-100000@achilles.silby.com> In-Reply-To: <200106231730.f5NHUNd73058@earth.backplane.com>
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On Sat, 23 Jun 2001, Matt Dillon wrote: > Yes, there's no question bzero() should be removed. The subroutine > overhead alone, never mind it doing anything, is enough to blow away > any benefit. Hence: > > Test3 - man load w/ptrs 35.73 nS/loop > Test4 - mlptrs & bzero 161.60 nS/loop > > Ouch! Of course, us old timers also see the fact that the entire > subroutine runs dozens of instructions in less then a microsecond and > say "ooooh, cool...". > > -Matt Wow! Thanks for the optimization, I hadn't considered that bzero could be so slow. I'm about to take off right now, I'll see if I can mock up some benchmarks of the overall performance of tcp_output when I get back on Monday. Mike "Silby" Silbersack To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message
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