Messages in this thread | | | Date | Wed, 16 Nov 2005 07:01:40 -0800 (PST) | From | Kenny Simpson <> | Subject | Re: mmap over nfs leads to excessive system load |
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--- Trond Myklebust <trond.myklebust@fys.uio.no> wrote: > Anyhow, does the following patch help?
Unfortunately, not:
samples % symbol name 545009 15.2546 find_get_pages_tag 450595 12.6120 mpage_writepages 383196 10.7255 release_pages 381479 10.6775 unlock_page 351513 9.8387 clear_page_dirty_for_io 317784 8.8947 pci_conf1_write 167918 4.7000 __lookup_tag 160701 4.4980 page_waitqueue 59142 1.6554 _spin_lock_irqsave 47655 1.3338 skb_copy_bits 39136 1.0954 __wake_up_bit 38143 1.0676 _read_lock_irqsave
With reducing the window size to 32k, things aren't much different: samples % symbol name 474589 21.2001 find_get_pages_tag 370512 16.5509 mpage_writepages 310556 13.8727 release_pages 302571 13.5160 unlock_page 286541 12.7999 clear_page_dirty_for_io 119717 5.3478 page_waitqueue 109920 4.9102 __lookup_tag 33313 1.4881 pci_conf1_write 29198 1.3043 __wake_up_bit 27075 1.2095 _read_lock_irqsave 25009 1.1172 _read_unlock_irq
... except the performance is much worse than with the 2M buffer (hence the 2M choice). With the smaller buffer, the throughput starts at 8M/sec and quickly drops to 1M/sec.
-Kenny
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