Messages in this thread | | | Date | Wed, 24 Jun 2015 11:16:50 +0200 | From | Michal Hocko <> | Subject | Re: Write throughput impaired by touching dirty_ratio |
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On Wed 24-06-15 10:27:36, Vlastimil Babka wrote: > [add some CC's] > > On 06/19/2015 05:16 PM, Mark Hills wrote: [...] > > The system is an HP xw6600, running i686 kernel. This happens whether
How many CPUs does the machine have?
> > internal SATA HDD, SSD or external USB drive is used. I first saw this on > > kernel 4.0.4, and 4.0.5 is also affected.
OK so this is 32b kernel which might be the most important part. What is the value of /proc/sys/vm/highmem_is_dirtyable? Also how does your low mem vs higmem look when you are setting the ratio (cat /proc/zoneinfo)?
It seems Vlastimil is right and a bogus ratelimit_pages is calculated and your writers are throttled every few pages. -- Michal Hocko SUSE Labs
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