-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 MARK CALLAGHAN wrote: > On Mon, Mar 16, 2009 at 10:57 AM, Brian Aker <[email protected]> wrote: >> FYI (This was an internal reply I made, but I believe anyone on the list >> would find it interesting). >> >> Begin forwarded message: >> >>> Hi! >>> >>> On Mar 16, 2009, at 1:29 AM, Jay Pipes wrote: >>> >>>> Frankly, libevent is being used entirely incorrectly in pool_of_threads >>>> plugin... >>> Yep! >>> >>> Though even in its current state if you are doing just primary key lookups >>> it will outperform the threaded handler (spin up slap on the key test). The >>> problem is that you need to be able to catch a IO event on a non-blocking >>> port to make better use of it. > > Jay, > > Can you give more details on the case where pool-of-threads makes > anything faster? I have no problem making sysbench throughput 2X > slower when pool-of-threads is used with MySQL 6.0. > http://bugs.mysql.com/bug.php?id=42288
I didn't say that; krow did. I've never seen pool-of-threads perform better than the multi-thread scheduler for anything and most times it can't even make it past 16 threads in benchmarks. I hacked up a new scheduler yesterday which uses a scoreboard system and am waiting for krow to merge my latest changes into trunk so I can benchmark it. I'll keep the list updated on that. > Did drizzle make significant changes to this when porting it? No. it's almost identical to 6.0. Cheers, Jay >>> Though... the problem still exists that a port that continues to "block" >>> will hold up any other transactions that will conflict. In the current state >>> this is a bit worse then what it should be because we are not releasing to >>> another sessions well enough (aka... we need to do this on IO event). Even >>> fixing that though... this type of scheduler will only really work for cases >>> were you have short transactions, or a large amount of read IO. In the end, >>> libevent just gives us a scheduler for one particular type of IO. >>> >>> Long term? Some sort of scheduler that can grow or shrink... or possibly >>> something where we can really do priority in the queries (aka... connect >>> into the optimizer and use estimated cost). >>> >>> Cheers, >>> -Brian >> -- >> _______________________________________________________ >> Brian "Krow" Aker, brian at tangent.org >> Seattle, Washington >> http://krow.net/ <-- Me >> http://tangent.org/ <-- Software >> _______________________________________________________ >> You can't grep a dead tree. >> >> >> >> >> _______________________________________________ >> Mailing list: https://launchpad.net/~drizzle-discuss >> Post to : [email protected] >> Unsubscribe : https://launchpad.net/~drizzle-discuss >> More help : https://help.launchpad.net/ListHelp >> > > > -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iEYEARECAAYFAkm+qp0ACgkQ2upbWsB4UtHStgCfbv5IznOltpwuwPS5p2IlbxwS Qh8An3aGPcarFR5uVZ5y26oervY8YF90 =HPbK -----END PGP SIGNATURE----- _______________________________________________ Mailing list: https://launchpad.net/~drizzle-discuss Post to : [email protected] Unsubscribe : https://launchpad.net/~drizzle-discuss More help : https://help.launchpad.net/ListHelp
