hyperthreading locks up sleeping threads

Tim Peters tim.peters at gmail.com
Mon May 8 23:29:15 CEST 2006

[OlafMeding at gmail.com]
> Below are 2 files.  The first is a Python program that isolates the
> problem within less than 1 hour (often just a few minutes).

It does not on my box.  I ran that program, from a DOS shell, using
the released Windows Python 2.4.3.  After an hour, it was still
printing.  I left it running, and started a second instance of the
test program from another DOS box.  That was 4 hours ago, and both
instances are still printing.

> ...
> Note, the Python programs hangs (stops responding) with hyper-threading
> turned on (a BIOS setting), but works as expected with hyper-threading
> turned off.

Hyper-threading was turned on here.

> ...
> Note, the Windows task manager shows 2 CPUs on the Performance tab with
> hyper-threading is turned on.

Same here, although do note that whether the Performance tab shows one
or two CPUs when HT is enabled depends on how the user sets Task
Manager's View -> CPU History option.

> Both Python 2.3.5 and 2.4.3 (downloaded from python.org) have this
> problem.

I used the python.org 2.4.3.

> The operating system is MS Windows XP Professional.

Same here.

> winmsd.exe shows:
> 2CPUs: x86 Family 15 Model 4 Stepping 1 GenuineIntel ~3000 MHz
> Version: 5.1.2600 Service Pack 2 Build 2600

Different processor here:

2CPUs: x86 Family 15 Model 3 Stepping 4 GenuineIntel ~3400 Mhz
Version	5.1.2600 Service Pack 2 Build 2600

> Could someone with a hyper-threading (or dual core or multi processor)
> CPU please confirm this bug?

Not me, and I'm tired of trying :-)

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