Messages in this thread | | | From | Dimitrios Apostolou <> | Subject | Re: 2.6.36 io bring the system to its knees | Date | Mon, 1 Nov 2010 01:09:34 +0000 (UTC) |
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Hello,
On Sun, 31 Oct 2010 09:51:32 +0800, Wu Fengguang wrote: > It may also help to lower the dirty ratio. > > echo 5 > /proc/sys/vm/dirty_ratio > > Memory pressure + heavy write can easily hurt responsiveness. > > - eats up to 20% (the default value for dirty_ratio) memory with dirty > pages and hence increase the memory pressure and number of swap IO
My experience has been different with that. Wouldn't it make more sense to _increase_ dirty_ratio (to 50 lets say) and at the same time decrease dirty_background_ratio? That way writing to disk starts early, but the related apps stall waiting for I/O only when dirty_ratio is reached.
Thanks, Dimitris
> > - the file copy makes the device write congested and hence makes > pageout() easily blocked in get_request_wait() > > As a result every application may be slowed down by the heavy swap IO > when page fault as well as being blocked when allocating memory (which > may go into direct reclaim and then call pageout()). > > Thanks, > Fengguang
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