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Date:   Fri, 23 Sep 2022 08:21:54 -0700
From:   Christoph Hellwig <hch@infradead.org>
To:     Jens Axboe <axboe@kernel.dk>
Cc:     Christoph Hellwig <hch@infradead.org>, linux-block@vger.kernel.org,
        linux-scsi@vger.kernel.org, linux-nvme@lists.infradead.org
Subject: Re: [PATCHSET 0/5] Enable alloc caching and batched freeing for
 passthrough
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On Fri, Sep 23, 2022 at 09:19:15AM -0600, Jens Axboe wrote:
> On 9/23/22 9:16 AM, Christoph Hellwig wrote:
> > On Thu, Sep 22, 2022 at 12:28:00PM -0600, Jens Axboe wrote:
> >> This is good for a 10% improvement for passthrough performance. For
> >> a non-drive limited test case, passthrough IO is now more efficient
> >> than the regular bdev O_DIRECT path.
> > 
> > How so?  If it ends up faster we are doing something wrong in the
> > normal path as there should be no fundamental difference in the work
> > that is being done.
> 
> There's no fundamental difference, but the bdev path is more involved
> than the simple passthrough path.

Well, I guess that means there is some more fat we need to trim
then..