Thread (25 messages) flat view 25 messages, 12 authors, 2007-02-25

Re: all syscalls initially taking 4usec on a P4? Re: nonblocking UDPv4 recvfrom() taking 4usec @ 3GHz?

From: Pavel Machek <hidden>
Date: 2007-02-25 10:42:06
Also in: lkml

Hi!
quoted
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
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