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Re: Thread pool (request for review)



>>>>> "Vladislav" == Vladislav Vaintroub <wlad@xxxxxxxxxxxxxxxx> writes:

Vladislav> Hello,
Vladislav> Worklog#246  http://askmonty.org/worklog/Server-BackLog/?tid=246  is ready
Vladislav> to review.   The worklog is implemented in
Vladislav> lp:~maria-captains/maria/5.5-threadpool, and if someone prefers to have a
Vladislav> one big diff, it is in the attachment(diff.diff)

Vladislav> It would be great if Monty, Serg (optionally Kristian if there is interest)
Vladislav> could take a some time to review it in the near future. The worklog has
Vladislav> extensive description of the implementation, might be helpful to consult it
Vladislav> before reviewing.

I will look at this tomorrow.

Vladislav> The branch currently has thread-handling=pool-if-threads as default, I found
Vladislav> it easier for testing.  Based on results of benchmark (see below),  it seems
Vladislav> to be generally performing well. So maybe we should use it as default, beta
Vladislav> version of 5.5 for better testing coverage . Maybe we can keep it as new
Vladislav> default after testing default, if there are no complains.

We should probably not have this as default as the behavior if you
have many long running queries with the thread pool will be much worse
than with one-thread-per-connection.

Vladislav> Benchmarking:

Vladislav> I also run some sysbench on 3 machines (2 Linuxes - fb-maria1 with 16 cores
Vladislav> and pitbull with 24 cores, and windows one with 8 cores but good IO),
Vladislav> results in
Vladislav> https://docs.google.com/spreadsheet/ccc?key=0AqvHLyfRWjmbdDY0U1MzZGlXY3VGdUx
Vladislav> xcC1pUlBZeHc 
Vladislav> I used sysbench 0.4 to run some of "unit" oltp tests (point-select and
Vladislav> update-nokey), as well as mere "classic" OLTP-readonly and OLTP-readwrite.
Vladislav> All tests are run with number of concurrent clients ranging from 16 to 4096,
Vladislav> with warm cache, with sysbench table having 1Mio records.

Vladislav> The results seem to be quite different on all of the machines tested (the
Vladislav> machines are very different, in terms of cores, IO etc) , yet threadpool has
Vladislav> a positive effect on all 3 machines, and the positive effect seems to grow
Vladislav> with the number of cores.

Please work with Axel to make a benchmark article out of the above.



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