[issue7946] Convoy effect with I/O bound threads and New GIL

[Nir Aides]

Nir Aides <nir at winpdb.org> added the comment:

A link to ccbench results comparing old GIL, old GIL with long check interval, new GIL and BFS:
http://bugs.python.org/file17370/nir-ccbench-linux.log

Summary:

Results for ccbench latency and bandwidth test run on Ubuntu Karmic 64bit, q9400 2.6GHz, all Python versions built with computed gotos optimization.

Old GIL:
Hi level of context switching and reduced performance. 
~90ms IO latency with pure Python CPU bound background threads and low IO bandwidth results.

Old GIL with sys.setcheckinterval(2500) as done by Zope:
Context switching level back to normal.
IO latency shoots through the roof. ~950ms (avg) is the maximum recordable value in this test since CPU load duration is 2sec.

New GIL:
The expected 5ms wait related IO latency and low IO bandwidth.

BFS patch:
Behaves.

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