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Improved InnoDB rw_lock patch

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There is patch from Google to improve SMP performance , but for some workloads it showed for us reverse scalability.
E.g. update_key benchmark from sysbench. There are also results with Yasufumi’s rw_locks (http://bugs.mysql.com/bug.php?id=26442)

Threads Standard InnoDB Google smpfix Yasufumi rw_lock
1 9700.28 10601.96 9432.44
2 14355.66 16673.31 12783.58
4 16104.20 2669.39 6308.92
8 18507.55 780.22 1854.43
16 16178.09 842.73 1601.05
32 12337.50 2028.89 3274.13
64 7801.18 1911.94 4043.85

results are in tps, more are better

(result in tps, more is better)
The benchmark was made on 8cores box, and as you see for 4+ threads we have worse results than for 2 threads. That is was main reason why we did not include InnoDB smp fixes in our build yet.

Fortunately we get fixed version of Yasufumu’s rw_locks and you can download them there

The results for the same benchmark:

Threads Standard InnoDB Yasufumi rw_lock ver 2
1 9700.28 9812.18
2 14355.66 14602.46
4 16104.20 18726.22
8 18507.55 19099.80
16 16178.09 17470.22
32 12337.50 12407.24
64 7801.18 7669.73

And for other workloads new rw_locks show results comparable with Google’s smpfix, so we will include
innodb_rw_lock into our next -percona-highperf release

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Vadim Tkachenko

Vadim leads Percona's development group, which produces the Percona Server, Percona Server for MongoDB, Percona XtraDB Cluster and Percona XtraBackup. He is an expert in solid-state storage, and has helped many hardware and software providers succeed in the MySQL market.


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Percona Software

  • Do you have any benchmarks from some of the other tests?


  • Vadim Post author


    We have benchmarks for DBT2, but results should be better prepared before we publishing them.


  • Many thanks to Yasufumi for his innodb_rw_lock patch. I was close to loosing my trust in FreeBSD before applying the patch. Running our 7G InnoDB database on MySql 5.0.67 on FreeBSD 7.0 on a 8core Box we had severe context-switching problems without the patch. After applying it it works like a charm. Close to no contentions left!


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