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SubjectRe: mmap over nfs leads to excessive system load
On Tue, Nov 15, 2005 at 03:47:30PM -0800, Kenny Simpson wrote:
> 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

67%, or 2/3 of the samples, are in the top 6 functions. Have you tried
instruction-level profiling? It would be interesting to see what
codepaths within the functions are the largest offenders.


-- wli
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