Antoine Pitrou skrev:
Kristján sent me a patch which I applied and is supposed to fix this.
Anyway, thanks for the numbers. The GIL does seem to fare a bit better (zero
latency with the Pi calculation in the background) than under Linux, although it
may be caused by the limited resolution of time.time() under Windows.
My critisism of the GIL on python-ideas was partly motivated by this:
http://blip.tv/file/2232410
However, David Beazley is not talking about Windows. Since the GIL is
apparently not a mutex on Windows, it could behave differently. So I
wrote a small script that contructs a GIL battle, and record how often a
check-interval results in a thread-switch or not. For monitoring check
intervals, I used a small C extension to read _Py_Ticker from ceval.c.
It is not declared static so I could easily hack into it.
With two threads and a check interval og 100, only 61 of 100000 check
intervals failed to produce a thread-switch in the interpreter. I'd call
that rather fair. :-)
And in case someone asks, the nthreads=1 case is just for verification.
S.M.
D:\>test.py
check interval = 1
nthreads=1, swiched=0, missed=100000
nthreads=2, swiched=57809, missed=42191
nthreads=3, swiched=91535, missed=8465
nthreads=4, swiched=99751, missed=249
nthreads=5, swiched=95839, missed=4161
nthreads=6, swiched=100000, missed=0
D:\>test.py
check interval = 10
nthreads=1, swiched=0, missed=100000
nthreads=2, swiched=99858, missed=142
nthreads=3, swiched=99992, missed=8
nthreads=4, swiched=100000, missed=0
nthreads=5, swiched=100000, missed=0
nthreads=6, swiched=100000, missed=0
D:\>test.py
check interval = 100
nthreads=1, swiched=0, missed=100000
nthreads=2, swiched=99939, missed=61
nthreads=3, swiched=100000, missed=0
nthreads=4, swiched=100000, missed=0
nthreads=5, swiched=100000, missed=0
nthreads=6, swiched=100000, missed=0
D:\>test.py
check interval = 1000
nthreads=1, swiched=0, missed=100000
nthreads=2, swiched=99999, missed=1
nthreads=3, swiched=100000, missed=0
nthreads=4, swiched=100000, missed=0
nthreads=5, swiched=100000, missed=0
nthreads=6, swiched=100000, missed=0
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