syscall cost freebsd vs linux ?

Sergey Kandaurov pluknet at
Tue Nov 27 00:02:46 UTC 2012

On 26 November 2012 15:39, Lukasz Wojcik <lukasz.wojcik at> 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


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