Date: Sat, 16 Feb 2002 14:03:31 -0800 (PST) From: Matthew Dillon <dillon@apollo.backplane.com> To: Alfred Perlstein <bright@mu.org> Cc: Poul-Henning Kamp <phk@critter.freebsd.dk>, arch@FreeBSD.ORG, jhb@FreeBSD.ORG, peter@wemm.org, jake@locore.ca Subject: Re: gettimeofday() and crhold()/crfree() (was Re: gettimeofday() and copyout(). Is copyout() MPSAFE on non-i386 archs? ) Message-ID: <200202162203.g1GM3Vu39770@apollo.backplane.com> References: <6988.1013844797@critter.freebsd.dk> <200202162033.g1GKXOf13029@apollo.backplane.com> <20020216214709.GA12136@elvis.mu.org>
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This is interesting: SHELL1> ./tg & SHELL1> ./tg & ... 255000 gettimeofday calls per second each SHELL1> ./tg SHELL2> ./tg ... 322000 gettimeofday calls per second each I think this is due to the same ucred being shared from the two ./tg runs from the same shell, indication further mutex contention above and beyond whatever contention was occuring before with separate instances of the ucred (due to sshd setuid'ing and such when starting a new shell). I'm not proposing any changes, this is just another data point that we may want to keep in mind. -Matt Matthew Dillon <dillon@backplane.com> To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message
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