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From: Sven Schmidt <4sschmid@informatik.uni-hamburg.de>
To: Minchan Kim <minchan@kernel.org>
Cc: ebiggers3@gmail.com, akpm@linux-foundation.org,
	bongkyu.kim@lge.com, rsalvaterra@gmail.com,
	sergey.senozhatsky@gmail.com, gregkh@linuxfoundation.org,
	linux-kernel@vger.kernel.org, herbert@gondor.apana.org.au,
	davem@davemloft.net, linux-crypto@vger.kernel.org,
	anton@enomsg.org, ccross@android.com, keescook@chromium.org,
	tony.luck@intel.com
Subject: Re: [PATCH v7 0/5] Update LZ4 compressor module
Date: Mon, 13 Feb 2017 13:08:41 +0100	[thread overview]
Message-ID: <20170213120841.GB22510@bierbaron.springfield.local> (raw)
In-Reply-To: <20170213000324.GA5379@bbox>

On Mon, Feb 13, 2017 at 09:03:24AM +0900, Minchan Kim wrote:
> Hi Sven,
> 
> On Sun, Feb 12, 2017 at 12:16:17PM +0100, Sven Schmidt wrote:
> > 
> > 
> > 
> > On 02/10/2017 01:13 AM, Minchan Kim wrote:
> > > Hello Sven,
> > >
> > > On Thu, Feb 09, 2017 at 11:56:17AM +0100, Sven Schmidt wrote:
> > >> Hey Minchan,
> > >>
> > >> On Thu, Feb 09, 2017 at 08:31:21AM +0900, Minchan Kim wrote:
> > >>> Hello Sven,
> > >>>
> > >>> On Sun, Feb 05, 2017 at 08:09:03PM +0100, Sven Schmidt wrote:
> > >>>>
> > >>>> This patchset is for updating the LZ4 compression module to a version based
> > >>>> on LZ4 v1.7.3 allowing to use the fast compression algorithm aka LZ4 fast
> > >>>> which provides an "acceleration" parameter as a tradeoff between
> > >>>> high compression ratio and high compression speed.
> > >>>>
> > >>>> We want to use LZ4 fast in order to support compression in lustre
> > >>>> and (mostly, based on that) investigate data reduction techniques in behalf of
> > >>>> storage systems.
> > >>>>
> > >>>> Also, it will be useful for other users of LZ4 compression, as with LZ4 fast
> > >>>> it is possible to enable applications to use fast and/or high compression
> > >>>> depending on the usecase.
> > >>>> For instance, ZRAM is offering a LZ4 backend and could benefit from an updated
> > >>>> LZ4 in the kernel.
> > >>>>
> > >>>> LZ4 homepage: http://www.lz4.org/
> > >>>> LZ4 source repository: https://github.com/lz4/lz4
> > >>>> Source version: 1.7.3
> > >>>>
> > >>>> Benchmark (taken from [1], Core i5-4300U @1.9GHz):
> > >>>> ----------------|--------------|----------------|----------
> > >>>> Compressor      | Compression  | Decompression  | Ratio
> > >>>> ----------------|--------------|----------------|----------
> > >>>> memcpy          |  4200 MB/s   |  4200 MB/s     | 1.000
> > >>>> LZ4 fast 50     |  1080 MB/s   |  2650 MB/s     | 1.375
> > >>>> LZ4 fast 17     |   680 MB/s   |  2220 MB/s     | 1.607
> > >>>> LZ4 fast 5      |   475 MB/s   |  1920 MB/s     | 1.886
> > >>>> LZ4 default     |   385 MB/s   |  1850 MB/s     | 2.101
> > >>>>
> > >>>> [1] http://fastcompression.blogspot.de/2015/04/sampling-or-faster-lz4.html
> > >>>>
> > >>>> [PATCH 1/5] lib: Update LZ4 compressor module
> > >>>> [PATCH 2/5] lib/decompress_unlz4: Change module to work with new LZ4 module version
> > >>>> [PATCH 3/5] crypto: Change LZ4 modules to work with new LZ4 module version
> > >>>> [PATCH 4/5] fs/pstore: fs/squashfs: Change usage of LZ4 to work with new LZ4 version
> > >>>> [PATCH 5/5] lib/lz4: Remove back-compat wrappers
> > >>>
> > >>> Today, I did zram-lz4 performance test with fio in current mmotm and
> > >>> found it makes regression about 20%.
> > >>>
> > >>> "lz4-update" means current mmots(git://git.cmpxchg.org/linux-mmots.git) so
> > >>> applied your 5 patches. (But now sure current mmots has recent uptodate
> > >>> patches)
> > >>> "revert" means I reverted your 5 patches in current mmots.
> > >>>
> > >>>                      revert    lz4-update
> > >>>
> > >>>       seq-write       1547       1339      86.55%
> > >>>      rand-write      22775      19381      85.10%
> > >>>        seq-read       7035       5589      79.45%
> > >>>       rand-read      78556      68479      87.17%
> > >>>    mixed-seq(R)       1305       1066      81.69%
> > >>>    mixed-seq(W)       1205        984      81.66%
> > >>>   mixed-rand(R)      17421      14993      86.06%
> > >>>   mixed-rand(W)      17391      14968      86.07%
> > >>
> > >> which parts of the output (as well as units) are these values exactly?
> > >> I did not work with fio until now, so I think I might ask before misinterpreting my results.
> > >
> > > It is IOPS.
> > >
> > >>  
> > >>> My fio description file
> > >>>
> > >>> [global]
> > >>> bs=4k
> > >>> ioengine=sync
> > >>> size=100m
> > >>> numjobs=1
> > >>> group_reporting
> > >>> buffer_compress_percentage=30
> > >>> scramble_buffers=0
> > >>> filename=/dev/zram0
> > >>> loops=10
> > >>> fsync_on_close=1
> > >>>
> > >>> [seq-write]
> > >>> bs=64k
> > >>> rw=write
> > >>> stonewall
> > >>>
> > >>> [rand-write]
> > >>> rw=randwrite
> > >>> stonewall
> > >>>
> > >>> [seq-read]
> > >>> bs=64k
> > >>> rw=read
> > >>> stonewall
> > >>>
> > >>> [rand-read]
> > >>> rw=randread
> > >>> stonewall
> > >>>
> > >>> [mixed-seq]
> > >>> bs=64k
> > >>> rw=rw
> > >>> stonewall
> > >>>
> > >>> [mixed-rand]
> > >>> rw=randrw
> > >>> stonewall
> > >>>
> > >>
> > >> Great, this makes it easy for me to reproduce your test.
> > >
> > > If you have trouble to reproduce, feel free to ask me. I'm happy to test it. :)
> > >
> > > Thanks!
> > >
> > 
> > Hi Minchan,
> > 
> > I will send an updated patch as a reply to this E-Mail. Would be really grateful If you'd test it and provide feedback!
> > The patch should be applied to the current mmots tree.
> > 
> > In fact, the updated LZ4 _is_ slower than the current one in kernel. But I was not able to reproduce such large regressions
> > as you did. I now tried to define FORCE_INLINE as Eric suggested. I also inlined some functions which weren't in upstream LZ4,
> > but are defined as macros in the current kernel LZ4. The approach to replace LZ4_ARCH64 with the function call _seemed_ to behave
> > worse than the macro, so I withdrew the change.
> > 
> > The main difference is, that I replaced the read32/read16/write... etc. functions using memcpy with the other ones defined 
> > in upstream LZ4 (which can be switched using a macro). 
> > The comment of the author stated, that they're as fast as the memcpy variants (or faster), but not as portable
> > (which does not matter since we're not dependent for multiple compilers).
> > 
> > In my tests, this version is mostly as fast as the current kernel LZ4.
> 
> With a patch you sent, I cannot see enhancement so I wanted to dig in and
> found how I was really careless.
> 
> I have tested both test with CONFIG_KASAN. OMG. With disabling it, I don't
> see any regression any more. So, I'm really really *sorry* about noise and
> wasting your time. However, I am curious why KASAN makes such difference.
> 

Hey Minchan,

I'm glad to hear that! Nevertheless, the changes discussed here made some differences in my own tests (I believe it got a bit
faster now) and we have the functions properly inlined, where this makes sense. Also, I added the '-O3' C-flag as Eric suggested.
So, this was not really a waste of time, I think.

> The reason I tested new updated lz4 is description says lz4 fast and
> want to use it in zram. How can I do that? and How faster it is compared
> to old?
>

Unfortunately, in the current implementation (in crypto/lz4.c, which is used by zram) I'm setting the acceleration parameter 
(which is the paramer making the compression 'fast', see LZ4_compress_fast) to 1 (which is the default) since I did not know how this
patchset is accepted and this equals the behaviour currently available in kernel.

Basically, the logic is 'higher acceleration = faster compression = lower compression ratio' and vice versa. 
I included some benchmarks in my patch 0/5 E-Mail taken from the official LZ4:

> > >>>> ----------------|--------------|----------------|----------
> > >>>> Compressor      | Compression  | Decompression  | Ratio
> > >>>> ----------------|--------------|----------------|----------
> > >>>> memcpy          |  4200 MB/s   |  4200 MB/s     | 1.000
> > >>>> LZ4 fast 50     |  1080 MB/s   |  2650 MB/s     | 1.375
> > >>>> LZ4 fast 17     |   680 MB/s   |  2220 MB/s     | 1.607
> > >>>> LZ4 fast 5      |   475 MB/s   |  1920 MB/s     | 1.886
> > >>>> LZ4 default     |   385 MB/s   |  1850 MB/s     | 2.101
> > >>>>

fast 50 means: acceleration=50, default: acceleration=1.

Besides the proposed patchset, I tried to implement a module parameter in crypto/lz4.c to set the acceleration factor.
In my tests, the module parameter works out great.
But I think this is subject to a future, separate patch. Especially since I had to 'work around' the crypto/testmgr.c, 
which only tests acceleration=1 and there's no limit for acceleration.  

Thanks for your help,

Sven

  reply	other threads:[~2017-02-13 12:08 UTC|newest]

Thread overview: 84+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1482259992-16680-1-git-send-email-4sschmid@informatik.uni-hamburg.de>
     [not found] ` <1482259992-16680-2-git-send-email-4sschmid@informatik.uni-hamburg.de>
2016-12-22 13:25   ` [PATCH 1/3] crypto: Change lz4 modules to work with new lz4 compressor module version Sergey Senozhatsky
2017-01-07 16:55 ` [PATCH v2 0/4] Update LZ4 compressor module Sven Schmidt
2017-01-07 16:55   ` [PATCH v2 1/4] lib: Update LZ4 compressor module based on LZ4 v1.7.2 Sven Schmidt
2017-01-08 11:22     ` Greg KH
2017-01-10  9:32       ` Sven Schmidt
2017-01-10  9:59         ` Greg KH
2017-01-08 11:25     ` Greg KH
2017-01-08 11:33       ` Rui Salvaterra
2017-01-10  9:21       ` Sven Schmidt
2017-01-10 10:00         ` Greg KH
2017-01-10 10:50           ` Willy Tarreau
2017-01-07 16:55   ` [PATCH v2 2/4] lib/decompress_unlz4: Change module to work with new LZ4 module version Sven Schmidt
2017-01-08 11:23     ` Greg KH
2017-01-07 16:55   ` [PATCH v2 3/4] crypto: Change LZ4 modules " Sven Schmidt
2017-01-07 16:55   ` [PATCH v2 4/4] fs/pstore: fs/squashfs: Change usage of LZ4 to comply " Sven Schmidt
2017-01-07 21:33     ` Kees Cook
2017-01-10  9:45       ` Sven Schmidt
2017-01-21 15:09 ` [PATCH v3 0/4] Update LZ4 compressor module Sven Schmidt
2017-01-21 15:09   ` [PATCH 1/4] lib: " Sven Schmidt
2017-01-21 15:56     ` kbuild test robot
2017-01-21 16:16     ` kbuild test robot
2017-01-21 17:38     ` kbuild test robot
2017-01-22 11:05     ` Greg KH
2017-01-21 15:09   ` [PATCH 2/4] lib/decompress_unlz4: Change module to work with new LZ4 module version Sven Schmidt
2017-01-21 15:09   ` [PATCH 3/4] crypto: Change LZ4 modules " Sven Schmidt
2017-01-21 15:09   ` [PATCH 4/4] fs/pstore: fs/squashfs: Change usage of LZ4 to work with new LZ4 version Sven Schmidt
2017-01-22 19:35 ` [PATCH v4 0/4] Update LZ4 compressor module Sven Schmidt
2017-01-22 19:35   ` [PATCH v4 1/4] lib: " Sven Schmidt
2017-01-24  0:23     ` Andrew Morton
2017-01-24 16:48       ` Sven Schmidt
2017-01-22 19:35   ` [PATCH v4 2/4] lib/decompress_unlz4: Change module to work with new LZ4 module version Sven Schmidt
2017-01-22 19:35   ` [PATCH v4 3/4] crypto: Change LZ4 modules " Sven Schmidt
2017-01-22 19:35   ` [PATCH v4 4/4] fs/pstore: fs/squashfs: Change usage of LZ4 to work with new LZ4 version Sven Schmidt
2017-01-26  7:57 ` [PATCH v5 0/5] Update LZ4 compressor module Sven Schmidt
2017-01-26  7:57   ` [PATCH v5 1/5] lib: " Sven Schmidt
2017-01-26  7:57   ` [PATCH v5 2/5] lib/decompress_unlz4: Change module to work with new LZ4 module version Sven Schmidt
2017-01-26  7:57   ` [PATCH v5 3/5] crypto: Change LZ4 modules " Sven Schmidt
2017-01-26  7:57   ` [PATCH v5 4/5] fs/pstore: fs/squashfs: Change usage of LZ4 to work with new LZ4 version Sven Schmidt
2017-01-26  7:57   ` [PATCH v5 5/5] lib/lz4: Remove back-compat wrappers Sven Schmidt
2017-01-26  9:19   ` [PATCH v5 0/5] Update LZ4 compressor module Eric Biggers
2017-01-26 14:15     ` Sven Schmidt
2017-01-27 22:01 ` [PATCH v6 " Sven Schmidt
2017-01-27 22:02   ` [PATCH v6 1/5] lib: " Sven Schmidt
2017-01-31 22:27     ` Jonathan Corbet
2017-02-01 20:18       ` Sven Schmidt
2017-01-27 22:02   ` [PATCH v6 2/5] lib/decompress_unlz4: Change module to work with new LZ4 module version Sven Schmidt
2017-01-27 22:02   ` [PATCH v6 3/5] crypto: Change LZ4 modules " Sven Schmidt
2017-01-27 22:02   ` [PATCH v6 4/5] fs/pstore: fs/squashfs: Change usage of LZ4 to work with new LZ4 version Sven Schmidt
2017-01-27 22:02   ` [PATCH v6 5/5] lib/lz4: Remove back-compat wrappers Sven Schmidt
2017-02-05 19:09 ` [PATCH v7 0/5] Update LZ4 compressor module Sven Schmidt
2017-02-05 19:09   ` [PATCH v7 1/5] lib: " Sven Schmidt
2017-02-05 19:09   ` [PATCH v7 2/5] lib/decompress_unlz4: Change module to work with new LZ4 module version Sven Schmidt
2017-02-05 19:09   ` [PATCH v7 3/5] crypto: Change LZ4 modules " Sven Schmidt
2017-02-05 19:09   ` [PATCH v7 4/5] fs/pstore: fs/squashfs: Change usage of LZ4 to work with new LZ4 version Sven Schmidt
2017-02-05 19:09   ` [PATCH v7 5/5] lib/lz4: Remove back-compat wrappers Sven Schmidt
2017-02-08 23:31   ` [PATCH v7 0/5] Update LZ4 compressor module Minchan Kim
2017-02-09  0:24     ` Eric Biggers
2017-02-09  5:24       ` Eric Biggers
2017-02-09 11:05         ` Sven Schmidt
2017-02-09 18:20           ` Eric Biggers
2017-02-10  0:14         ` Minchan Kim
2017-02-09 11:02       ` Sven Schmidt
2017-02-09 18:29         ` Eric Biggers
2017-02-10  3:57           ` David Miller
2017-02-09 10:56     ` Sven Schmidt
2017-02-10  0:13       ` Minchan Kim
2017-02-12 11:16         ` Sven Schmidt
2017-02-12 11:16           ` [PATCH] lz4: fix performance regressions Sven Schmidt
2017-02-12 13:05             ` Willy Tarreau
2017-02-12 15:20               ` Sven Schmidt
2017-02-12 21:41                 ` Willy Tarreau
2017-02-13 11:53                   ` Sven Schmidt
2017-02-13 13:37                     ` Willy Tarreau
2017-02-12 23:38             ` Eric Biggers
2017-02-14 10:33               ` Sven Schmidt
2017-02-13  0:03           ` [PATCH v7 0/5] Update LZ4 compressor module Minchan Kim
2017-02-13 12:08             ` Sven Schmidt [this message]
2017-02-15  7:29               ` Minchan Kim
2017-02-15 18:16 ` [PATCH v8 " Sven Schmidt
2017-02-15 18:16   ` [PATCH v8 1/5] lib: " Sven Schmidt
2017-02-15 18:16   ` [PATCH v8 2/5] lib/decompress_unlz4: Change module to work with new LZ4 module version Sven Schmidt
2017-02-15 18:16   ` [PATCH v8 3/5] crypto: Change LZ4 modules " Sven Schmidt
2017-02-15 18:16   ` [PATCH v8 4/5] fs/pstore: fs/squashfs: Change usage of LZ4 to work with new LZ4 version Sven Schmidt
2017-02-15 18:16   ` [PATCH v8 5/5] lib/lz4: Remove back-compat wrappers Sven Schmidt

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