2 x quad-core system is slower that 2 x dual core on FreeBSD
lol at chistydom.ru
Thu Nov 22 03:44:21 PST 2007
Kris Kennaway wrote:
>>> In the meantime there is unfortunately not a lot that can be done,
>>> AFAICT. There is one hack that I will send you later but it is not
>>> likely to help much. I will also think about how to track down the
>>> cause of the contention further (the profiling trace only shows that
>>> it comes mostly from vget/vput but doesn't show where these are
>>> called from).
>> Actually this patch might help. It doesn't replace lockmgr but it
>> does fix a silly thundering herd behaviour. It probably needs some
>> adjustment to get it to apply cleanly (it is about 7 months old), and
>> I apparently stopped using it because I ran into deadlocks. It might
>> be stable enough to at least see how much it helps.
> Try this one instead, it applies to HEAD. You'll need to manually enter
> the paths though because of how p4 mangles diffs.
Finally I tried your patch and it seems to help a little.
Now FreeBSD 7-STABLE ULE 8-core server without optimized PHP
realpath_cache_size (producing 2000+ lstats per request) can handle up
to ~24 rps as opposed to max. 17 rps without your patch. %sys never
grows over %user with your patch. On the server with optimized
realpath_cache_size there's no visible influence of your patch.
However Linux is still 2 times faster for my workload and there should
also be another ways for optimization.
With best regards,
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