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Date:      Tue, 18 Sep 2007 11:34:16 -0400
From:      "Philip M. Gollucci" <philip@ridecharge.com>
To:        "freebsd-questions@freebsd.org" <freebsd-questions@freebsd.org>
Cc:        Kris Kennaway <kris@FreeBSD.org>
Subject:   Re: MySQL config [WAS: ]uilding a new workstation - dual or quad-core CPU for FreeBSD 7?
Message-ID:  <46EFEFF8.7070202@ridecharge.com>
In-Reply-To: <46EFED9B.7010300@ridecharge.com>
References:  <26ddd1750709141351i3646e9bdg8d8b7e93461167f9@mail.gmail.com>		<bef9a7920709141441r5c228a8bu1fcf2ea15868c3c@mail.gmail.com>		<26ddd1750709151014x2112b022r9bcb999fbf1e7e49@mail.gmail.com>		<46EC270A.3020100@FreeBSD.org>		<8cb6106e0709151421h7bfdeb6fo7dc671820294e9c7@mail.gmail.com>		<46EC4F59.7070104@FreeBSD.org>		<8cb6106e0709151435p72cd328by63895421f3a63ea4@mail.gmail.com>		<46EC50DA.6000104@FreeBSD.org>	<8cb6106e0709151446x4c54a520u2d5cd543ba1541e@mail.gmail.com>	<46EC55B8.2090107@FreeBSD.org>	<46EEE3ED.6080304@ridecharge.com> <46EF21C2.7010104@FreeBSD.org> <46EFED9B.7010300@ridecharge.com>

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Philip M. Gollucci wrote:
>>> my.cnf
>>> innodb_thread_concurrency = 8
>> You want '0' or performance will suck.  There's a basic architectural
>> flaw in how mysql handles non-zero concurrency values here (innodb
>> accesses are serialized by a global mutex that protects a counter to
>> check if it should try to allow more innodb concurrency.  Duh.)
>>
>> Anyway, assuming your disks can keep up you should see a big performance
>> boost when you switch to 7.0.  This is a fairly big "if" though: I don't
>> know if it's even feasible for a write-heavy database to saturate 8 CPUs
>> instead of being bottlenecked by disk speeds and leaving the CPUs mostly
from /usr/local/share/my-innodb-heavy-4G.cnf

# This permits the application to give the threads system a hint for the
# desired number of threads that should be run at the same time.  This
# value only makes sense on systems that support the
# thread_concurrency()
# function call (Sun Solaris, for example).
# You should try [number of CPUs]*(2..4) for thread_concurrency
thread_concurrency = 8

# Number of IO threads to use for async IO operations. This value is
# hardcoded to 4 on Unix, but on Windows disk I/O may benefit from a
# larger number.
innodb_file_io_threads = 4

# Number of threads allowed inside the InnoDB kernel. The optimal value
# depends highly on the application, hardware as well as the OS
# scheduler properties. A too high value may lead to thread thrashing.
innodb_thread_concurrency = 16


Apparently its only set in this file.

We should probably submit a bug to MySQL rather then add a patch to
ports or do both and remove the ports when its released.


-- 
------------------------------------------------------------------------
Philip M. Gollucci (philip@ridecharge.com) c:323.219.4708 o:703.749.9295x206
Senior System Admin - Riderway, Inc.
http://riderway.com / http://ridecharge.com
1024D/EC88A0BF 0DE5 C55C 6BF3 B235 2DAB  B89E 1324 9B4F EC88 A0BF

Work like you don't need the money,
love like you'll never get hurt,
and dance like nobody's watching.




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