2 x quad-core system is slower that 2 x dual core on FreeBSD
kris at FreeBSD.org
Fri Nov 30 01:28:14 PST 2007
Alexey Popov wrote:
> Kris Kennaway wrote:
>> One more patch which may or may not help is:
>> (may also require porting since it was against an older version of
>> 7.0-CURRENT). When I have tested this in the past it was a
>> performance loss for reasons that I think I understand (basically, it
>> is locally a performance improvement for the name cache but also
>> requires a fixed lockmgr to avoid an overall performance loss), but I
>> don't remember if I tested it in conjunction with the lockmgr patch.
> This patch doesn't apply to 7-STABLE because /sys/kern/vfs_cache.c was
> changed significanly since rev. 1.108. I tried to patch it manually but
> don't know what to do with cache_lookup() changes.
OK, I am about to go on vacation so I am not able to help with either of
>>>> There are patches you need to enable it on woodcrest. They are in
>>>> my p4 branch (kris-contention) but I don't have time right now to
>>>> extract them.
>>> I think it would be very useful because I can't see any other ways to
>>> profile FreeBSD on the modern many-cores machines.
>> You can extract the changeset from my branch via
>> http://perforce.freebsd.org. Unfortunately I don't have time to do it
> I'll try it if it does not also need porting.
> With best regards,
> Alexey Popov
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