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Date:   Wed, 28 Aug 2019 11:20:23 -0400
From:   "Theodore Y. Ts'o" <tytso@mit.edu>
To:     Shaokun Zhang <zhangshaokun@hisilicon.com>
Cc:     linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org,
        Yang Guo <guoyang2@huawei.com>,
        Andreas Dilger <adilger.kernel@dilger.ca>,
        Eric Biggers <ebiggers@kernel.org>
Subject: Re: [PATCH v2] ext4: use percpu_counters for extent_status cache
 hits/misses
Message-ID: <20190828152023.GG24857@mit.edu>
Mail-Followup-To: "Theodore Y. Ts'o" <tytso@mit.edu>,
        Shaokun Zhang <zhangshaokun@hisilicon.com>,
        linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org,
        Yang Guo <guoyang2@huawei.com>,
        Andreas Dilger <adilger.kernel@dilger.ca>,
        Eric Biggers <ebiggers@kernel.org>
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On Wed, Aug 28, 2019 at 05:19:17PM +0800, Shaokun Zhang wrote:
> From: Yang Guo <guoyang2@huawei.com>
> 
> @es_stats_cache_hits and @es_stats_cache_misses are accessed frequently in
> ext4_es_lookup_extent function, it would influence the ext4 read/write
> performance in NUMA system. Let's optimize it using percpu_counter,
> it is profitable for the performance.
> 
> The test command is as below:
> fio -name=randwrite -numjobs=8 -filename=/mnt/test1 -rw=randwrite
> -ioengine=libaio -direct=1 -iodepth=64 -sync=0 -norandommap
> -group_reporting -runtime=120 -time_based -bs=4k -size=5G
> 
> And the result is better 10% than the initial implement:
> without the patch，IOPS=197k, BW=770MiB/s (808MB/s)(90.3GiB/120002msec)
> with the patch,  IOPS=218k, BW=852MiB/s (894MB/s)(99.9GiB/120002msec)
> 
> Cc: "Theodore Ts'o" <tytso@mit.edu>
> Cc: Andreas Dilger <adilger.kernel@dilger.ca>
> Cc: Eric Biggers <ebiggers@kernel.org>
> Signed-off-by: Yang Guo <guoyang2@huawei.com>
> Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com>

Thanks, applied.

						- Ted