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Open Source and information security mailing list archives
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Date: Tue, 20 Feb 2007 09:04:58 +0100 From: bert hubert <bert.hubert@...herlabs.nl> To: Stephen Hemminger <shemminger@...ux-foundation.org> Cc: netdev@...r.kernel.org Subject: Re: nonblocking UDPv4 recvfrom() taking 4usec @ 3GHz? On Mon, Feb 19, 2007 at 03:56:23PM -0800, Stephen Hemminger wrote: > > Linux 2.6.20-rc4 appears to take 4 microseconds on my P4 3GHz for a > > non-blocking UDPv4 recvfrom() call, both on loopback and ethernet. > > > > Linux 2.6.18 on my 64 bit Athlon64 3200+ takes a similar amount of time. > > recvfrom itself is a tad worrisome, x=recvfrom. I didn't ask for the > > 'libc_enable_asynccancel' stuff. I'm trying to isolate the actual syscall > > but it is proving hard work for an assemnly newbie like me - socketcall > > doesn't make things easier. Together with Zwane Mwaikambo, we managed to isolate the pure syscall, it doesn't make a difference, a single recvfrom continues to take around 4 microseconds at 3GHz. Many thanks to Zwane for helping out. > Use oprofile to find the hotspot. Will do this next - I need to get me a setup where I can do oprofile *and* decent query rates, I don't do oprofile on my remote machines I don't have easy access to. Thanks. -- http://www.PowerDNS.com Open source, database driven DNS Software http://netherlabs.nl Open and Closed source services - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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