xfs - high CPU usage when removing files

xfs - high CPU usage when removing files

[Radoslaw Garbacz]

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Hi,

I noticed a high CPU usage when removing files from XFS partition on Linux,
CentOS (always close to 100%).
Is it a known issue, or is it more likely to be attributed to my testing
methodology ('time' command)?

Thanks in advance,

-- 
Best Regards,

Radoslaw Garbacz

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Re: xfs - high CPU usage when removing files

[Dave Chinner]

On Mon, May 13, 2013 at 01:28:47PM -0500, Radoslaw Garbacz wrote:
> Hi,
> 
> I noticed a high CPU usage when removing files from XFS partition on Linux,
> CentOS (always close to 100%).
> Is it a known issue, or is it more likely to be attributed to my testing
> methodology ('time' command)?

If you are removing extremely fragmented files, then 100% CPU will
be seen.  If you are removing tens of thousands of small files, then
100% CPU will be seen,

IOWs, if there's enough work to be done, removing files will use all
the available CPU. There's no problem with that.

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

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Re: xfs - high CPU usage when removing files

[Stefan Ring]

>> I noticed a high CPU usage when removing files from XFS partition on Linux,
>> CentOS (always close to 100%).
>> Is it a known issue, or is it more likely to be attributed to my testing
>> methodology ('time' command)?
>
> If you are removing extremely fragmented files, then 100% CPU will
> be seen.  If you are removing tens of thousands of small files, then
> 100% CPU will be seen,
>
> IOWs, if there's enough work to be done, removing files will use all
> the available CPU. There's no problem with that.

Also, removing huge files which are completely in cache (recently
written, for example) will use considerable CPU time.

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