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Message-ID: <8b080deb-adcc-4490-8e1d-5be789b1fcff@i-love.sakura.ne.jp>
Date:   Thu, 16 Dec 2021 01:02:12 +0900
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Subject: Re: [loop] e3f9387aea: stress-ng.loop.ops_per_sec 78.9% improvement
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To:     kernel test robot <oliver.sang@intel.com>
Cc:     Jens Axboe <axboe@kernel.dk>, Christoph Hellwig <hch@lst.de>,
        LKML <linux-kernel@vger.kernel.org>, lkp@lists.01.org,
        lkp@intel.com, ying.huang@intel.com, feng.tang@intel.com,
        zhengjun.xing@linux.intel.com, fengwei.yin@intel.com
References: <20211215135803.GA34913@xsang-OptiPlex-9020>
From:   Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
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On 2021/12/15 22:58, kernel test robot wrote:
> 
> 
> Greeting,
> 
> FYI, we noticed a 78.9% improvement of stress-ng.loop.ops_per_sec due to commit:
> 
> 
> commit: e3f9387aea67742b9d1f4de8e5bb2fd08a8a4584 ("loop: Use pr_warn_once() for loop_control_remove() warning")
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master
> 

Avoiding printk() flooding will reduce latency, but I'm curious
why the testing program is trying ioctl(fd, LOOP_CTL_REMOVE, -1) ?
Since such ioctl() is pointless, measuring ops_per_sec is also pointless...