From: "John Hawkes" <hawkes@sgi.com>
To: linux-ia64@vger.kernel.org
Subject: Re: should ia64_spinlock_contention do backoff?
Date: Sun, 28 Mar 2004 02:37:39 +0000 [thread overview]
Message-ID: <00c101c4146d$bf3f1630$6400a8c0@PCJohn> (raw)
In-Reply-To: <200403251941.i2PJfrTH026392@napali.hpl.hp.com>
> >>>>> Chris Wedgwood wrote on Fri, March 26, 2004 3:41 PM
> > Does anyone have any idea what locks are most heavily contented for
> > ia64 right now?
>
> This question is a bit too broad, lock contention highly depends on
workload.
I totally agree.
On one AIM7-like workload that I'm using, at 64p the dominant contention is
doing pte_chain_lock() in page_remove_rmap() (11% of the cycles) and
page_add_rmap() (5%). That's not spinlock contention -- it's cacheline
contention. That same workload at 96p shows about 47% of the kernel cycles in
find_get_page() doing the spin_lock(mapping->page_lock), and the
pte_chain_lock() bottleneck has faded into insignificance.
John Hawkes
next prev parent reply other threads:[~2004-03-28 2:37 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-03-25 19:41 should ia64_spinlock_contention do backoff? David Mosberger
2004-03-25 20:06 ` John Hawkes
2004-03-25 22:13 ` Keith Owens
2004-03-25 22:28 ` David Mosberger
2004-03-26 17:16 ` markw
2004-03-26 23:41 ` Chris Wedgwood
2004-03-26 23:44 ` David Mosberger
2004-03-27 0:14 ` Chen, Kenneth W
2004-03-28 2:37 ` John Hawkes [this message]
2004-03-28 19:23 ` Matthew Wilcox
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