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Date: Fri, 22 Sep 2017 19:31:45 +0200
From: Greg KH <gregkh@linuxfoundation.org>
To: Eduardo Valentin <eduval@amazon.com>
Cc: stable@vger.kernel.org, shli@fb.com, neilb@suse.com, colyli@suse.de
Subject: Re: [stable v4.9.y] Backports to fix fstrim time / CPU load on raid0
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On Fri, Sep 22, 2017 at 10:16:06AM -0700, Eduardo Valentin wrote:
> Hello GregKH,
> 
> I have been seeing several reports of performance issue with raid0 while performing fstrim on v4.9.y.
> Currently, if one performs:
> 
> # fio --name fio_test_file --direct=1 --rw=randwrite --bs=4k --size=5G --numjobs=8 --group_reporting --directory=/mount/raid0 
> # rm -rf /media/nvme-raid0 
> # time fstrim -vvv -a 
> real	3m41.102s 
> user	0m0.000s 
> sys	0m4.964s 

Also, is this a regression from older kernels?

thanks,

greg k-h