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Message-ID: <20051115234731.9539.qmail@web34105.mail.mud.yahoo.com>
Date: Tue, 15 Nov 2005 15:47:30 -0800 (PST)
From: Kenny Simpson <theonetruekenny@yahoo.com>
Subject: re: mmap over nfs leads to excessive system load
To: linux kernel <linux-kernel@vger.kernel.org>
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I ran the same test again against 2.6.15-rc, and got pretty much the same thing.  It starts nice
and fast (30+MB/s, but drops down to under 10MB/s with the system time pegging one CPU).

Here is the oprofile result:

CPU: P4 / Xeon with 2 hyper-threads, speed 2658.47 MHz (estimated)
Counted GLOBAL_POWER_EVENTS events (time during which processor is not stopped) with a unit mask
of 0x01 (mandatory) count 100000
samples  %        symbol name
412585   14.6687  find_get_pages_tag
343898   12.2267  mpage_writepages
290144   10.3155  release_pages
288631   10.2617  unlock_page
286181   10.1746  pci_conf1_write
267619    9.5147  clear_page_dirty_for_io
128128    4.5554  __lookup_tag
120895    4.2982  page_waitqueue
52739     1.8750  _spin_lock_irqsave
43623     1.5509  skb_copy_bits
30157     1.0722  __wake_up_bit
29973     1.0656  _read_lock_irqsave


-Kenny


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