Hi,
Is it the same limitation problem about the performance under mysql with a
lot of IO ?
I test FreeBSD-4.3 pthread and linux 2.2.16 pthread under same servers (ram,
dd etc...) with mysql and same databases exactly. When I doing a request of
about 57000 rows on a 4000000 rows database under linux I can have 1,70s of
elapsed time and under FreeBSD, I have 2.89s for the same request. I see
that Linux doing a lot of IO cache (buffered = 502556K and cached = 335160K,
servers have 1 Go of memory) but FreeBSD limits to a little cache and 112 Mo
buffered, the rest of memory is Free. I'm a FreeBSD fan, but I see that I
cannot use FreeBSD for a mysql box production that do a lot of selects
(index on memory doesn't change anything). I try to use softupdates but
there is a little amelioration. Sinisa of mysql dev team says to me that
reason lies in much more efficient context-switching, more efficient file
system and much better buffering. So what is the difference about linux
caching and FreeBSD ? is the vfs_bio architecure responsible of this lack of
performance ?
If someone can tell me how can I boost performance of caching under FreeBSD
to have the same performance, please tell me :)
If this problem is due to another problem and You know what is this problem
tell me how too.
I hope that FreeBSD can run mysql thread native as faster as possible in the
future.
Thank you for any clues.
Regards,
Sebastien Petit.
--
[EMAIL PROTECTED]
> How is performance dismal under redhat? FreeBSD should do a really
> good job of running thousands of threads as long as you don't have
> too much disk IO since all the threads are multiplexed into a single
> process, if you have an IO intensive program FreeBSD threads will
> probably not help you all that much. There are plans on replacing
> the FreeBSD threads library with a multiplexed userland<->kernel
> scheme in the near future.
>
>
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