imports and python locking

[John A Meinel]

Martin Pool wrote:
> On 21 Jul 2005, Neal Becker <ndbecker2 at gmail.com> wrote:
>  
> 
>>What distro are you testing on?  Is this a modern glibc with nptl?
> 
> 
> Ubuntu Hoary, libc6-2.3.2.ds1-20ubuntu13.
> 
> The attached c file demonstrates the problem when compiled with "gcc
> -lpthread".  Compiling with -march=686 (in the hope of using cmpxchg or
> something) does not help.  Run it under strace and observe thousands of
> pointless futex calls.
> 

Doing a strace with python2.4.1 on Fedora Core 4 also shows a bunch of 
futex calls. What is weird is that it does quite a bit of work first.

What I'm seeing is that between each lstat, it has 6 futex calls.

Then later on, there are long lists of just futex calls.

So yes, this happens on other machines too.

John
=:->

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