Re: [PATCH v34 00/13] Introduce Data Access MONitor (DAMON)

From: SeongJae Park <sj38.park@gmail.com>
To: SeongJae Park <sj38.park@gmail.com>
Cc: Dongjoo Seo <dseo3@uci.edu>,
	"Jonathan.Cameron@huawei.com" <Jonathan.Cameron@Huawei.com>,
	acme@kernel.org, akpm@linux-foundation.org,
	alexander.shishkin@linux.intel.com, amit@kernel.org,
	benh@kernel.crashing.org, brendanhiggins@google.com,
	corbet@lwn.net, david@redhat.com, dwmw@amazon.com,
	elver@google.com, fan.du@intel.com, foersleo@amazon.de,
	greg@kroah.com, gthelen@google.com, guoju.fgj@alibaba-inc.com,
	jgowans@amazon.com, joe@perches.com, linux-damon@amazon.com,
	linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-mm@kvack.org, mgorman@suse.de, mheyne@amazon.de,
	minchan@kernel.org, mingo@redhat.com, namhyung@kernel.org,
	peterz@infradead.org, riel@surriel.com, rientjes@google.com,
	rostedt@goodmis.org, rppt@kernel.org, shakeelb@google.com,
	shuah@kernel.org, sieberf@amazon.com, sjpark@amazon.de,
	snu@zelle79.org, vbabka@suse.cz, vdavydov.dev@gmail.com,
	zgf574564920@gmail.com
Subject: Re: [PATCH v34 00/13] Introduce Data Access MONitor (DAMON)
Date: Mon, 26 Jul 2021 13:32:30 +0000	[thread overview]
Message-ID: <20210726133230.1959-1-sjpark@amazon.de> (raw)
In-Reply-To: <20210723083042.2720-1-sjpark@amazon.de>

From: SeongJae Park <sjpark@amazon.de>

On Fri, 23 Jul 2021 08:30:41 +0000 SeongJae Park <sj38.park@gmail.com> wrote:

> From: SeongJae Park <sjpark@amazon.de>
> 
> Hello Dongjoo,
> 
> 
> On Fri, 23 Jul 2021 16:02:44 +0900 Dongjoo Seo <dseo3@uci.edu> wrote:
> 
> > Hello, I am new user of this amazing tool.
> 
> Thank you!  It's always great to meet a new user!
> 
> > I want to use this tool for Nvidia tx2 board with kernel version 4.9.140.
> > 
> > Do you guys have any timeline or update schedule for different kernel version compatibility?
> 
> I didn't have such a plan until now, but I think I can find a time slot to do
> one-time back porting of current DAMON on 4.9.140.  I think continuous support
> would be not so easy, though.  Nevertheless, if you need that, please feel free
> to let me know.  Once it's done, I will notify you.

Thank you for waiting.  I back-ported this patchset and another one for the
physical address space monitoring[1] on v4.9.140.  The source code is available
at DAMON development tree[2].

BTW, I can also agree to Greg's opinion.  For the reason, I also back-ported
the patches on latest v4.9.y[3].  I'd like to suggest you to try that first if
possible.  I also hope this patchset to be merged in mainline in near future,
so that NVIDIA be attracted by DAMON and thus forward-port their drivers on the
latest mainline version.

Nevertheless, DAMOS[4] and DAMON_RECLAIM[5] patchsets are not back-ported
because those need more works, and you are apparently interested in only the
monitoring part.

Please note that this backport is for only one-time.  In other words, I will
not backport the patches for every future 4.9.y release.  Nevertheless, if you
need another backport, please remember I'm here for you.

Finally, a disclaimer.  I did only minimal test for this, as below:

    $ git clone https://github.com/sjp38/masim; make -C masim/
    $ git clone https://github.com/awslabs/damo
    $ # monitor a virtual address space of a process
    $ sudo ./damo/damo record "./masim/masim ./masim/configs/zigzag.cfg"
    $ ./damo/damo report heats --heatmap stdout
    [...]
    88888888888888888888888888888888888888600000000000000000000000000000000000000000
    88888888888888888888888888888888888888600000000000000000000000000000000000000000
    44444444444444444444444444444444444444444444444444444444444444444444444444444200
    00000000000000000000000000000000000000288888888888888888888888888888888888888400
    00000000000000000000000000000000000000288888888888888888888888888888888888888400
    55555555555555555555555555555555555555422222222222222222222222222222222222222100
    88888888888888888888888888888888888888600000000000000000000000000000000000000000
    88888888888888888888888888888888888888600000000000000000000000000000000000000000
    [...]
    # x-axis: space (140021718388736-140021924798416: 196.848 MiB)
    # y-axis: time (247055083700-317341924740: 1 m 10.287 s)
    # resolution: 80x40 (2.461 MiB and 1.757 s for each character)
    $ # monitor the physcial address space of the system
    $ ./masim/masim ./masim/configs/zigzag.cfg &
    $ sudo ./damo/damo record paddr
    00000000000000000000000000000000000000000000000000000000000000000000000000000000
    00000000000000000000000000000000000000000000000000000000000000000000000000000020
    00000000000000000000000000000000000000000000000000000000000000000000000000000040
    [...]
    # x-axis: space (4294967296-136303345616: 122.942 GiB)
    # y-axis: time (356358198969-430518964169: 1 m 14.161 s)
    # resolution: 80x40 (1.537 GiB and 1.854 s for each character)

Hope you get some fun with these backports.

[1] https://lore.kernel.org/linux-mm/20201216094221.11898-1-sjpark@amazon.com/
[2] https://github.com/sjp38/linux/tree/damon/for-v4.9.140
[3] https://github.com/sjp38/linux/tree/damon/for-v4.9.276
[4] https://lore.kernel.org/linux-mm/20201216084404.23183-1-sjpark@amazon.com/
[5] https://lore.kernel.org/linux-mm/20210720131309.22073-1-sj38.park@gmail.com/

Thanks,
SeongJae Park

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