Re: Attribute spinlock contention ticks to caller.

From: David Mosberger-Tang <David.Mosberger_at_acm.org>
Date: 2005-09-17 11:08:45
On 9/16/05, Robin Holt <holt@sgi.com> wrote:

> Can you site one instance where it is more helpful to know that _ANY_
> lock in the system is hitting ia64_spinlock_contention as opposed to
> the function which has the spin_lock() code?  I can recall times when
> network traffic was contending on locks and causing my application to
> appear to have a contended lock.  With this change, at least we know
> the degradation is do to something external.

Not sure if I can help siting it, but I can cite one recent example: I
was looking at a profile of a test which wasn't supposed to have any
contention.  Yet, ia64_spinlock_contention unexpectedly showed up
fairly high in the profile.  Turns out it was due to some left-over
debug code.  Of course, I was using q-syscollect so it was easy to see
who was calling the spinlock contention routine a lot...

  --david

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Received on Sat Sep 17 11:09:29 2005

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