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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Andrew Hendry <andrew.hendry@gmail.com>
Cc: Jesper Dangaard Brouer <jdb@comx.dk>, netdev <netdev@vger.kernel.org>
Subject: Re: Loopback performance from kernel 2.6.12 to 2.6.37
Date: Tue, 09 Nov 2010 07:42:13 +0100	[thread overview]
Message-ID: <1289284933.2790.91.camel@edumazet-laptop> (raw)
In-Reply-To: <1289284715.2790.87.camel@edumazet-laptop>

Le mardi 09 novembre 2010 à 07:38 +0100, Eric Dumazet a écrit :

> Hmm, your clock source is HPET, that might explain the problem on a
> scheduler intensive workload.
> 

And if a packet sniffer (dhclient for example) makes all packets being
timestamped, it also can explain a slowdown, even if there is no
scheduler artifacts.

cat /proc/net/packet

> My HP dev machine
> # grep . /sys/devices/system/clocksource/clocksource0/*
> /sys/devices/system/clocksource/clocksource0/available_clocksource:tsc hpet acpi_pm 
> /sys/devices/system/clocksource/clocksource0/current_clocksource:tsc
> 
> My laptop:
> $ grep . /sys/devices/system/clocksource/clocksource0/*
> /sys/devices/system/clocksource/clocksource0/available_clocksource:tsc hpet acpi_pm 
> /sys/devices/system/clocksource/clocksource0/current_clocksource:tsc
> 




  reply	other threads:[~2010-11-09  6:42 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1288954189.28003.178.camel@firesoul.comx.local>
     [not found] ` <1288988955.2665.297.camel@edumazet-laptop>
     [not found]   ` <1289213926.15004.19.camel@firesoul.comx.local>
     [not found]     ` <1289214289.2820.188.camel@edumazet-laptop>
2010-11-08 15:06       ` Loopback performance from kernel 2.6.12 to 2.6.37 Eric Dumazet
2010-11-09  0:05         ` Andrew Hendry
2010-11-09  5:22           ` Eric Dumazet
2010-11-09  6:23             ` Eric Dumazet
2010-11-09  6:30               ` Andrew Hendry
2010-11-09  6:38                 ` Eric Dumazet
2010-11-09  6:42                   ` Eric Dumazet [this message]
2010-11-09 13:59         ` Jesper Dangaard Brouer
2010-11-09 14:06           ` Eric Dumazet
2010-11-09 14:16           ` Jesper Dangaard Brouer
2010-11-09 14:25             ` Eric Dumazet
2010-11-18 13:52               ` Eric Dumazet
2010-11-18 17:41                 ` Eric Dumazet
2010-11-18 17:48                   ` David Miller
2010-11-09 14:38             ` Jesper Dangaard Brouer
2010-11-10 11:24               ` Jesper Dangaard Brouer
2010-12-12 15:48                 ` Arnaldo Carvalho de Melo
2010-11-09 21:35 Xose Vazquez Perez
2010-11-10  8:49 ` Jesper Dangaard Brouer

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