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Message-ID: <20070225104154.GA2045@elf.ucw.cz> Date: Sun, 25 Feb 2007 11:41:54 +0100 From: Pavel Machek <pavel@....cz> To: Evgeniy Polyakov <johnpol@....mipt.ru> Cc: bert hubert <bert.hubert@...herlabs.nl>, Andi Kleen <andi@...stfloor.org>, netdev@...r.kernel.org, linux-kernel@...r.kernel.org Subject: Re: all syscalls initially taking 4usec on a P4? Re: nonblocking UDPv4 recvfrom() taking 4usec @ 3GHz? Hi! > > I've done so, with some interesting results. Source on > > http://ds9a.nl/tmp/recvtimings.c - be careful to adjust the '3000' divider > > to your CPU frequency if you care about absolute numbers! > > > > These are two groups, each consisting of 10 consecutive nonblocking UDP > > recvfroms, with 10 packets preloaded. Reported is the number of microseconds > > per recvfrom call which yielded a packet: > > > > $ ./recvtimings > > 4.142333 > > It can be recvfrom only problem - syscall overhead on my p4 (core duo, > debian testing) is bout 300 usec - to test I ran core duo is _not_ p4 class cpu; rsulets there will be very different. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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