Date: Wed, 25 Apr 2001 14:44:54 +0200 From: PETIT Sebastien <spetit@selectbourse.com> To: "'alfred@freebsd.org'" <alfred@freebsd.org> Cc: "'hackers@freebsd.org'" <hackers@freebsd.org> Subject: RE: Question about Posix Threads Message-ID: <D1AEA2C11FF0D3118A6700508BC220FC320D04@SBEXCHANGE>
next in thread | raw e-mail | index | archive | help
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. -- spe@kestaklan.net > 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. > > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?D1AEA2C11FF0D3118A6700508BC220FC320D04>