| innodb_thread_concurrency / cpu usage [message #362] |
Fri, 17 November 2006 16:35  |
 mmoeller
Messages: 2
Registered: November 2006 |
Junior Member |
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Hi,
we have a 4-way dualcore xeon server running mysql 5.0.27 with bufferpool-mutex-patch.
the load is entirely cpu/memory bound, no noticable disk activity.
If i set innodb_thread_concurrency to 16 or 32 and simulate a lot of load, i see that the system is overloaded but cpu usage is only at 20%.
If i set it to unlimited (0), i see cpu is going to 100%, but actually *less* queries are performed per second.
If i use SHOW MUTEX STATUS, the only mutex heavily used is the main bufferpool mutex, so I guess the concurrency problem is not entirely solved by the patch?
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| Re: innodb_thread_concurrency / cpu usage [message #368 is a reply to message #362 ] |
Mon, 20 November 2006 13:08  |
Peter
Messages: 405
Registered: August 2006 |
Senior Member
Super Guru |
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Also,
Can you report how much scalability do you get, ie if you can simulate your workload with 1 thread, 4 threads, 16 threads.
The interesting thing about current official patch is - it scales differently on different platforms and different workloads. For older Xeons it scales quite badly still. New (Woodcrest) Xeons are much better but still it can be far from perfect scalability depending on workload.
I have not had a chance to check on Opteron yet.
Peter Zaitsev, MySQL Performance Expert
MySQL Performance Blog - http://www.mysqlperformanceblog.com
MySQL Consulting http://www.mysqlperformanceblog.com/mysql-consulting/
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