From: Zou Nan hai <nanhai.zou@intel.com>
To: linux-kernel@vger.kernel.org
Subject: possible performance issue in 4-level page tables
Date: 01 Feb 2005 12:19:30 +0800 [thread overview]
Message-ID: <1107231570.2555.19.camel@linux-znh> (raw)
There is a performance regression of lmbench
lat_proc fork result on ia64.
in
2.6.10
I got
Process fork+exit:164.8438 microseconds.
in 2.6.11-rc2
Process fork+exit:183.8621 microseconds.
I believe this regression was caused by
the 4-level page tables change.
Since most of the kernel time spend in lat_proc fork is copy_page_range
in fork path and clear_page_range in the exit path. Now they are 1 level
deeper.
Though pud and pgd is same on IA64, there is still some overhead
introduced I think.
Are any other architectures seeing the same sort of results?
Zou Nan hai
next reply other threads:[~2005-02-01 5:46 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-02-01 4:19 Zou Nan hai [this message]
2005-02-01 7:46 ` possible performance issue in 4-level page tables Nick Piggin
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