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References: <20121119193202.GA79496@onelab2.iet.unipi.it>
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Date: Tue, 27 Nov 2012 03:02:45 +0300
Message-ID: <CAE-mSO+CSoUVb4QU93K6tVva+bcGtDj5ouJQhWiQsFHA-qCY4A@mail.gmail.com>
Subject: Re: syscall cost freebsd vs linux ?
From: Sergey Kandaurov <pluknet@gmail.com>
To: Lukasz Wojcik <lukasz.wojcik@zoho.com>
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Cc: Luigi Rizzo <rizzo@iet.unipi.it>, current@freebsd.org
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On 26 November 2012 15:39, Lukasz Wojcik <lukasz.wojcik@zoho.com> wrote:
> On 11/19/12 20:32, Luigi Rizzo wrote:
>>
>> today i was comparing the performance of some netmap-related code
>> on FreeBSD and Linux (RELENG_9 vs 3.2) and i was surprised to see that
>> our system calls are significantly slower.
>> On comparable hardware (i7-2600k vs E5-1650) the syscall
>> getppid() takes about 95ns on FreeBSD and 38ns on linux.
>>
>> (i make sure not to use gettimeofday(), which in linux is through vdso,
>> and getpid(), which is cached by glibc).
>>
>> Any idea on why there is this difference and whether/how
>> we can reduce it ?
>>
>
> I'm curious about how did you measure that ? Could you write some more about
> your methodology ?

There is a nice tool at /usr/src/tools/tools/syscall_timing

-- 
wbr,
pluknet