[Python-Dev] GIL behaviour under Windows

[John Arbash Meinel]

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Antoine Pitrou wrote:
>> I don't really know how this test works, so I won't claim to understand
>> the results either. However, here you go:
> 
> Thanks.
> 
> Interesting results. I wonder what they would be like on a multi-core
> machine. The GIL seems to behave perfectly on your setup (no performance
> degradation due to concurrency, and zero latencies).
> 

C:\downloads>C:\Python26\python.exe ccbench.py
- --- Throughput ---

Pi calculation (Python)

threads=1: 691 iterations/s.
threads=2: 400 ( 57 %)
threads=3: 453 ( 65 %)
threads=4: 467 ( 67 %)

^- seems to have some contention



regular expression (C)

threads=1: 592 iterations/s.
threads=2: 598 ( 101 %)
threads=3: 587 ( 99 %)
threads=4: 586 ( 99 %)

bz2 compression (C)

threads=1: 536 iterations/s.
threads=2: 1056 ( 196 %)
threads=3: 1040 ( 193 %)
threads=4: 1060 ( 197 %)


^- seems to properly show that I have 2 cores here.


- --- Latency ---

Background CPU task: Pi calculation (Python)

CPU threads=0: 0 ms. (std dev: 0 ms.)
CPU threads=1: 0 ms. (std dev: 0 ms.)
CPU threads=2: 0 ms. (std dev: 0 ms.)
CPU threads=3: 0 ms. (std dev: 0 ms.)
CPU threads=4: 0 ms. (std dev: 0 ms.)

Background CPU task: regular expression (C)

CPU threads=0: 0 ms. (std dev: 0 ms.)
CPU threads=1: 38 ms. (std dev: 18 ms.)
CPU threads=2: 173 ms. (std dev: 77 ms.)
CPU threads=3: 518 ms. (std dev: 264 ms.)
CPU threads=4: 661 ms. (std dev: 343 ms.)

Background CPU task: bz2 compression (C)

CPU threads=0: 0 ms. (std dev: 0 ms.)
CPU threads=1: 0 ms. (std dev: 0 ms.)
CPU threads=2: 0 ms. (std dev: 0 ms.)
CPU threads=3: 0 ms. (std dev: 0 ms.)
CPU threads=4: 0 ms. (std dev: 0 ms.)


John
=;->
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