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Date:   Sun, 5 Feb 2023 23:02:26 -0800
From:   Christoph Hellwig <hch@infradead.org>
To:     Qu Wenruo <quwenruo.btrfs@gmx.com>
Cc:     Christoph Hellwig <hch@infradead.org>, Qu Wenruo <wqu@suse.com>,
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Subject: Re: [PATCH 0/2] btrfs: reduce div64 calls for __btrfs_map_block()
 and its variants
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On Mon, Feb 06, 2023 at 02:58:55PM +0800, Qu Wenruo wrote:
> Right, I focused too much on the perf part, but sometimes the perf part may
> sound more scary:
> 
>   For example, DIVQ on Skylake has latency of 42-95 cycles [1] (and
>   reciprocal throughput of 24-90), for 64-bits inputs.
> 
> I'm not sure what's the best way to benchmark such thing.
> Maybe just do such division with random numbers and run it at module load
> time to verify the perf?

Honestly, getting rid of the ugly divisions calls is probably
reason enough as the series looks like a nice cleanup.  I just had
to nipick on the sentence.