Jap Pyck
2017-11-17 15:31:05 UTC
Hello,
I am new at pytables and particularly interested in the multi-thread
feature available through numexpr. I ran a few tests on a tables with 20
millions rows and 2 columns 'colA', 'colB' with MAX_NUMEXPR_THREADS set to
1, 2 and 4. The test was run on a MacPro 8cores.
Although I see the number of threads increases during the execution of the
query, the performance does not change.
It looks very similar to the limitation imposed by the GIL on
multi-threaded functions in python. I though that HDF5 could get around
this limitation.
Question: is there anything I missed or do wrong? Do I need to do
additional configuration changes to see a performance increase?
Thank you for your help
-JPK
I am new at pytables and particularly interested in the multi-thread
feature available through numexpr. I ran a few tests on a tables with 20
millions rows and 2 columns 'colA', 'colB' with MAX_NUMEXPR_THREADS set to
1, 2 and 4. The test was run on a MacPro 8cores.
Although I see the number of threads increases during the execution of the
query, the performance does not change.
It looks very similar to the limitation imposed by the GIL on
multi-threaded functions in python. I though that HDF5 could get around
this limitation.
Question: is there anything I missed or do wrong? Do I need to do
additional configuration changes to see a performance increase?
Thank you for your help
-JPK
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