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Date: Tue, 27 Jan 2026 16:16:09 +0100
From: Christoph Hellwig <hch@lst.de>
To: Anuj gupta <anuj1072538@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
	Christian Brauner <brauner@kernel.org>,
	"Darrick J. Wong" <djwong@kernel.org>,
	Carlos Maiolino <cem@kernel.org>,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	Anuj Gupta <anuj20.g@samsung.com>,
	Kanchan Joshi <joshi.k@samsung.com>, linux-block@vger.kernel.org,
	nvdimm@lists.linux.dev, linux-fsdevel@vger.kernel.org,
	linux-xfs@vger.kernel.org
Subject: Re: support file system generated / verified integrity information
Message-ID: <20260127151609.GA1883@lst.de>
References: <20260121064339.206019-1-hch@lst.de> <CACzX3AuDkwEw3v0bNmYLk8updk1ghVJa-T9o=EHXor9FA7badw@mail.gmail.com>
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On Tue, Jan 27, 2026 at 08:24:28PM +0530, Anuj gupta wrote:
> Hi Christoph,
> 
> Here are the QD1 latency numbers (in usec)

Thanks a lot!

Adding in the baseline numbers, as I wanted to compare those:

> Intel Optane:
> 
> Sequential read
>   | size | baseline | xfs-bounce |  xfs-pi  |
>   +------+----------+-----------+-----------+
>   |   4k |    7.18  |    13.62   |     7.20 |
>   |  64K |   36.40  |    99.66   |    34.16 |
>   |   1M |  206.38  |   258.88   |   306.23 |
>   +------+----------+------------+----------+

So for 4k and 64k reads we basically get back to the baseline.
The 1M numbers are puzzling, though.  I wonder if we need to
add WQ_CPU_INTENSIVE or do some other tweaks to the XFS I/O
completion workqueue so that we don't overload the scheduler.