On Monday 14 July 2008, Rune Torgersen wrote:
> Context switching - times in microseconds - smaller is better
> ------------------------------------------------------------------------
> Host OS 2p/0K 2p/16K 2p/64K 8p/16K 8p/64K 16p/16K 16p/64K
> ctxsw ctxsw ctxsw ctxsw ctxsw ctxsw ctxsw
> --------- ------------- ------ ------ ------ ------ ------ ------- -------
> 9919_unit Linux 2.6.25 20.6 86.2 28.5 103.8 38.7 111.8 57.4
> 9919_unit Linux 2.6.18 5.3300 63.2 17.9 73.4 23.1 74.9 26.2
This is certainly significant, but a lot has happened between the two
versions. I few ideas:
* compare some of the key configuration options:
# CONFIG_DEBUG_*
# CONFIG_PREEMPT*
# CONFIG_NO_HZ
# CONFIG_HZ
* Try looking at where the time is spent, using oprofile or readprofile
* Try setting /proc/sys/kernel/compat/sched_yield to 1, to get the legacy
behaviour of the scheduler.
* Maybe there is a kernel version that supports your hardware in both
arch/ppc/ and arch/powerpc. In that case, you could see if the platform
change had an impact.
Arnd <><
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