Comment 93 for bug 595047

Revision history for this message
In , thomas.pi (thomas.pi-linux-kernel-bugs) wrote :

No the patch does not fix the problem, but I think is now better than before.

I think, that it is a cpu scheduler problem. As one process with many threads and thread switching can nearby stop the execution of other processes. This problem exists in every kernel version, even 2.6.15. You can test it by executing the thread based with 2*100 threads.
My system starts to become unusable with the kernel 2.6.27 (Fedora 10) when executing the thread based test with 2*40-50 threads. I don't know how many interrupt occurs, while coping some data, but perhaps it is the commonness between copying files and the thread based test.

The provided bisect, points to a cpu scheduler performance regression, which make the problem more noticeable. The biggest cpu scheduler performance regression was in 2.6.24 - 2.6.27. There was another cpu scheduler performance regression between 2.6.22 and 2.6.24.