linux-ext4 - Re: High CPU Utilization When Copying to Ext4

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Message-ID: <4E174139.4070501@nasa.gov>
Date:	Fri, 8 Jul 2011 10:41:13 -0700
From:	Sean McCauliff <Sean.D.McCauliff@...a.gov>
To:	Andi Kleen <andi@...stfloor.org>
CC:	"Ted Ts'o" <tytso@....edu>,
	"linux-ext4@...r.kernel.org" <linux-ext4@...r.kernel.org>
Subject: Re: High CPU Utilization When Copying to Ext4

43% of the destination file system is in use.

Sean

On 07/08/2011 10:17 AM, Andi Kleen wrote:
> Sean McCauliff<Sean.D.McCauliff@...a.gov>  writes:
>
>> I tried running perf on the copy program on subset of the sparse
>> files. It seems like ext4 is the source of high cpu utilization.  At
>> this point this high cpu utilization is very annoying, but I can live
>> with this problem.  If you know something simple I could do to
>> alleviate this problem I would be most appreciative.  At the end of
>> this email is a consolidation of information about this problem.
>>
>> Events: 6M cycles
>> -76.80%     java  [kernel.kallsyms]      [k] ext4_mb_good_group
>>    - ext4_mb_good_group
>
> Is your file system too full?
>
> A lot of file system get inefficient in allocating blocks when the
> file system is nearly full.
>
> -Andi
>

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