Re: RFC: dirty_ratio back to 40%

From: Richard Kennedy
Date: Thu May 20 2010 - 09:48:05 EST


On 20/05/10 13:29, Heinz Diehl wrote:
> On 20.05.2010, Larry Woodman wrote:
> lwoodman@xxxxxxxxxx
>> Increasing the dirty_ratio to 40% will regain the performance loss seen
>> in several benchmarks. Whats everyone think about this???
>
> These are tuneable via sysctl. What I have in my /etc/sysctl.conf is
>
> vm.dirty_ratio = 4
> vm.dirty_background_ratio = 2
>
> This writes back the data more often and frequently, thus preventing the
> system from long stalls.
>
> Works at least for me. AMD Quadcore, 8 GB RAM.
>
get_dirty_limits uses a minimum vm_dirty_ratio of 5, so you can't set it
lower than that (unless you use vm_dirty_bytes).
But it's interesting that you find lowering the dirty_ratio helpful. Do
you have any benchmark results you can share?
regards
Richard
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