From: "Markus F.X.J. Oberhumer" <markus@oberhumer.com>
To: Johannes Stezenbach <js@sig21.net>
Cc: linux-kernel@vger.kernel.org, Andi Kleen <andi@firstfloor.org>,
chris.mason@fusionio.com, linux-btrfs@vger.kernel.org,
Nitin Gupta <ngupta@vflare.org>,
Richard Purdie <rpurdie@openedhand.com>,
richard -rw- weinberger <richard.weinberger@gmail.com>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [GIT PULL] Update LZO compression
Date: Wed, 15 Aug 2012 14:02:43 +0200 [thread overview]
Message-ID: <502B8FE3.7080501@oberhumer.com> (raw)
In-Reply-To: <20120814123937.GA14756@sig21.net>
Hi Johannes,
On 2012-08-14 14:39, Johannes Stezenbach wrote:
> On Tue, Aug 14, 2012 at 01:44:02AM +0200, Markus F.X.J. Oberhumer wrote:
>> On 2012-07-16 20:30, Markus F.X.J. Oberhumer wrote:
>>>
>>> As stated in the README this version is significantly faster (typically more
>>> than 2 times faster!) than the current version, has been thoroughly tested on
>>> x86_64/i386/powerpc platforms and is intended to get included into the
>>> official Linux 3.6 or 3.7 release.
>>>
>>> I encourage all compression users to test and benchmark this new version,
>>> and I also would ask some official LZO maintainer to convert the updated
>>> source files into a GIT commit and possibly push it to Linus or linux-next.
>
> Sorry for not reporting earlier, but I didn't have time to do real
> benchmarks, just a quick test on ARM926EJ-S using barebox,
> and found in the new version decompression is slower:
> http://lists.infradead.org/pipermail/barebox/2012-July/008268.html
I can only guess, but maybe your ARM cpu does not have an efficient
implementation of {get,put}_unaligned().
Could you please try the following patch and test if you can see
any significant speed difference?
Thanks,
Markus
diff --git a/lib/lzo/lzodefs.h b/lib/lzo/lzodefs.h
index ddc8db5..efc5714 100644
--- a/lib/lzo/lzodefs.h
+++ b/lib/lzo/lzodefs.h
@@ -12,8 +12,15 @@
*/
+#if defined(__arm__)
+#define COPY4(dst, src) \
+ (dst)[0] = (src)[0]; (dst)[1] = (src)[1]; \
+ (dst)[2] = (src)[2]; (dst)[3] = (src)[3]
+#endif
+#ifndef COPY4
#define COPY4(dst, src) \
put_unaligned(get_unaligned((const u32 *)(src)), (u32 *)(dst))
+#endif
#if defined(__x86_64__)
#define COPY8(dst, src) \
put_unaligned(get_unaligned((const u64 *)(src)), (u64 *)(dst))
>
> BTW, do you have userspace code matching the old and new
> lzo versions? It would be easier to benchmark.
>
> Unfortunately I cannot claim high confidence in my benchmark results
> due to missing time to do it properly, it would be useful if
> someone else could do some benchmarks on ARM before merging this.
>
>
> Johannes
--
Markus Oberhumer, <markus@oberhumer.com>, http://www.oberhumer.com/
next prev parent reply other threads:[~2012-08-15 12:02 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-13 23:44 [GIT PULL] Update LZO compression Markus F.X.J. Oberhumer
2012-08-14 3:15 ` Andi Kleen
2012-08-14 10:10 ` Markus F.X.J. Oberhumer
2012-08-14 12:39 ` Johannes Stezenbach
2012-08-15 12:02 ` Markus F.X.J. Oberhumer [this message]
2012-08-15 14:45 ` Johannes Stezenbach
2012-08-16 6:27 ` Markus F.X.J. Oberhumer
2012-08-16 15:06 ` Johannes Stezenbach
2012-08-16 17:25 ` Roman Mamedov
2012-08-16 17:52 ` Andi Kleen
2012-08-16 18:18 ` Geert Uytterhoeven
[not found] ` <CAPkEcwgv6f5B+Mrw7kzrHcZ5JZ+Yr0o=bLdoFqCB-e4CLiVx5A@mail.gmail.com>
2012-08-16 22:17 ` Andi Kleen
2012-08-17 1:23 ` Mitch Harder
2012-09-07 21:31 ` Andi Kleen
2012-08-16 15:21 ` Jeff Garzik
2012-08-16 16:20 ` Andi Kleen
2012-08-16 16:48 ` Jeff Garzik
2012-08-16 17:22 ` Johannes Stezenbach
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