Quoting Kris Kennaway <[EMAIL PROTECTED]>:

Michel Talon wrote:
On Mon, Jun 30, 2008 at 07:53:00PM +0200, Kris Kennaway wrote:
Yep, it could be that -- what confuses me though is that it is claimed that performance suddenly regressed. If so then this cannot be the underlying cause.

It may be that the load has augmented to the point that contention
imposes a rapid regression on throughput.

Yes, it could be that.  I don't know off-hand whether multiple threads
are counted separately by vmstat (at a guess I'd say no), but ps/top/etc
should show how many are active in the python process.

Just ran ktrace, and a bit of Googling seems to confirm my initial suspicion that the results I'm seeing are abnormal. The first several screenfulls of output look like this:

 52929 python2.4 1214867016.469416 CALL  kse_wakeup(0x811740c)
 52929 python2.4 0.000060 RET   kse_wakeup 0
 52929 python2.4 0.000008 RET   kse_release 0
 52929 python2.4 0.000040 CALL  kse_release(0x811df4c)
 52929 python2.4 0.000515 CALL  kse_wakeup(0x811740c)
 52929 python2.4 0.000012 RET   kse_wakeup 0
 52929 python2.4 0.000004 RET   kse_release 0
 52929 python2.4 0.000012 CALL  kse_release(0x811df4c)
 52929 python2.4 0.000365 CALL  kse_wakeup(0x811740c)
 52929 python2.4 0.000012 RET   kse_wakeup 0
 52929 python2.4 0.000003 RET   kse_release 0
 52929 python2.4 0.000010 CALL  kse_release(0x811df4c)
 52929 python2.4 0.000413 CALL  kse_wakeup(0x811740c)
 52929 python2.4 0.000011 RET   kse_wakeup 0
 52929 python2.4 0.000004 RET   kse_release 0
 52929 python2.4 0.000009 CALL  kse_release(0x811df4c)
 52929 python2.4 0.000393 CALL  kse_wakeup(0x811740c)
 52929 python2.4 0.000012 RET   kse_wakeup 0
 52929 python2.4 0.000004 RET   kse_release 0
 52929 python2.4 0.000009 CALL  kse_release(0x811df4c)

I may be mistaken, but it seems like that's a lot of unnecessary activity managing the threads; the confirmation I found came from http://arkiv.freebsd.se/?ml=freebsd-threads&a=2007-02&t=3178634.

Am I correct that this is abnormal behavior? If so, any idea what I may need to do to fix the issue?

Alex

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