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From: Vincent Fu <vincent.fu@samsung.com>
To: Jens Axboe <axboe@kernel.dk>,
	"fio@vger.kernel.org" <fio@vger.kernel.org>
Subject: RE: [PATCH 5/6] mem: try to parse /proc/meminfo to get huge page size
Date: Mon, 23 May 2022 22:56:13 +0000	[thread overview]
Message-ID: <a018febe94404c5ba4005e29c88c5902@samsung.com> (raw)
In-Reply-To: <3aeda4fc-4ea5-3dda-12c8-ed95403f9862@kernel.dk>

> -----Original Message-----
> From: Jens Axboe [mailto:axboe@kernel.dk]
> Sent: Monday, May 23, 2022 2:13 PM
> To: Vincent Fu <vincent.fu@samsung.com>; fio@vger.kernel.org
> Subject: Re: [PATCH 5/6] mem: try to parse /proc/meminfo to get huge
> page size
> 
> On 5/23/22 11:57 AM, Vincent Fu wrote:
> > Instead of relying on a platform-specific default huge page size, try to
> > parse /proc/meminfo to get the huge page size when it is not explicitly
> > specified as an option.
> 
> It's really sad that there isn't a nice way to get this information, but
> parsing meminfo will only get you one of them. Eg on my laptop:
> 
> axboe@m1 ~> cat /proc/meminfo | grep -i size
> Hugepagesize:      32768 kB
> 
> But if you look in:
> 
> axboe@m1 ~> ls /sys/kernel/mm/hugepages/
> hugepages-1048576kB/  hugepages-2048kB/  hugepages-32768kB/
> 
> and each directory has entries for increasing the number of them and
> how
> many are currently there.
> 
> Parsing /sys/kernel/mm/hugepages/ is probably a better idea than
> meminfo.
> 

Looking into this more, it seems that to do this 100% correctly will take more
time than I have.

However, I think this patch is still an improvement over a build-time default.
How about if I revise the documentation to say that fio will parse
/proc/meminfo (which reports the default huge page size) but YMMV and users
need to explicitly set the huge page size if they are using something else?

      reply	other threads:[~2022-05-23 22:56 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CGME20220523175712uscas1p20c6cf25d74d7616e5f3406db923b22c4@uscas1p2.samsung.com>
2022-05-23 17:57 ` [PATCH 0/6] cleanups, parse /proc/meminfo for huge page size Vincent Fu
2022-05-23 17:57   ` [PATCH 1/6] steadystate: delete incorrect comment Vincent Fu
2022-05-23 17:57   ` [PATCH 2/6] configure: refer to zlib1g-dev package for zlib support Vincent Fu
2022-05-23 17:57   ` [PATCH 4/6] t/run-fio-tests: improve json data decoding Vincent Fu
2022-05-23 17:57   ` [PATCH 3/6] HOWTO: add blank line for prettier formatting Vincent Fu
2022-05-23 17:57   ` [PATCH 6/6] docs: update for huge page size parsing Vincent Fu
2022-05-23 17:57   ` [PATCH 5/6] mem: try to parse /proc/meminfo to get huge page size Vincent Fu
2022-05-23 18:12     ` Jens Axboe
2022-05-23 22:56       ` Vincent Fu [this message]

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