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From: trajber@gmail.com (Mauro Romano Trajber)
To: kernelnewbies@lists.kernelnewbies.org
Subject: syscalls performance
Date: Fri, 25 Feb 2011 14:03:24 -0300	[thread overview]
Message-ID: <AANLkTimZac++X4jUsz2-bTTtEJwOR45NHAQ=GR3xCVnG@mail.gmail.com> (raw)

I was doing some performance tests of system calls and I find an interesting
behavior.
Using RDTSC to count the CPU cycles, a single call to the getpid() consumes
about 7k of CPU clock cycles and ten calls consume approximately 9,800
cycles.
The fact is that from the second call, the CPU cycles grows at a rate of
about 350 CPU cycles per call.
Why does this happen? There is some hardware optimization when the syscall
ID is already in EAX register ?

Any ideias ?
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             reply	other threads:[~2011-02-25 17:03 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-02-25 17:03 Mauro Romano Trajber [this message]
2011-02-25 17:15 ` syscalls performance Daniel Baluta
2011-02-25 18:22   ` Mauro Romano Trajber
2011-02-25 20:15     ` Daniel Baluta
2011-02-25 20:30       ` Mauro Romano Trajber
2011-02-25 20:42         ` Enrico Granata
2011-02-25 20:59           ` Jim Kukunas
2011-02-25 21:00             ` Enrico Granata
2011-02-25 22:03               ` Mauro Romano Trajber
2011-02-25 22:06                 ` Daniel Baluta
2011-02-25 22:14                   ` Enrico Granata
2011-02-26  4:31           ` Mulyadi Santosa
     [not found] <D3CBA33B-3809-4AF5-9F66-0F2D256C4A82@cs.ucsd.edu>
2011-02-25 17:14 ` Enrico Granata

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