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Date:   Mon, 11 Jul 2022 16:29:45 -0400 (EDT)
From:   Mikulas Patocka <mpatocka@redhat.com>
To:     Yu Kuai <yukuai1@huaweicloud.com>,
        Mike Snitzer <msnitzer@redhat.com>
cc:     agk@redhat.com, dm-devel@redhat.com, linux-kernel@vger.kernel.org,
        yukuai3@huawei.com, yi.zhang@huawei.com
Subject: Re: [PATCH] dm writecache: fix inaccurate reads/writes stats
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On Wed, 6 Jul 2022, Yu Kuai wrote:

> From: Yu Kuai <yukuai3@huawei.com>
> 
> Test procedures:
> 
> 1) format a dm writecache device with 4k blocksize.
> 2) flush cache.
> 3) cache 1G data through write.
> 4) clear stats.
> 5) read 2G data with bs=1m.
> 6) read stats.
> 
> Expected result:
> cache hit ratio is 50%.
> 
> Test result:
> stats: 0, 1011345, 749201, 0, 263168, 262144, 0, 0, 0, 0, 0, 0, 0, 0
> ratio is 99% (262144/263168)

Hi

Here I'm providing patches that change the dm-writecache counting from 
requests to blocks.

Mike, you can queue them for the next merge window.

Mikulas