linux-kernel - Re: [GIT PULL] Update LZO compression

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Thu, 16 Aug 2012 23:25:49 +0600
From:	Roman Mamedov <rm@...anrm.ru>
To:	Johannes Stezenbach <js@...21.net>
Cc:	"Markus F.X.J. Oberhumer" <markus@...rhumer.com>,
	linux-kernel@...r.kernel.org, Andi Kleen <andi@...stfloor.org>,
	chris.mason@...ionio.com, linux-btrfs@...r.kernel.org,
	Nitin Gupta <ngupta@...are.org>,
	Richard Purdie <rpurdie@...nedhand.com>,
	richard -rw- weinberger <richard.weinberger@...il.com>,
	linux-arm-kernel@...ts.infradead.org
Subject: Re: [GIT PULL] Update LZO compression

On Thu, 16 Aug 2012 17:06:47 +0200
Johannes Stezenbach <js@...21.net> wrote:

> Well, ~2x speedup on x86 is certainly a good achievement, but there
> are more ARM based devices than there are PCs, and I guess many
> embedded devices use lzo compressed kernels and file systems
> while I'm not convinced many PCs rely on lzo in the kernel.

Keep in mind that a major user of LZO is the BTRFS filesystem, and I believe it
is used much more often on larger machines than on ARM, in fact it had problems
operating on ARM at all, until quite recently.

> I know everyone's either busy or on vacation, but it would
> be so cool if someone could test on a more modern ARM core,
> with the userspace test code I posted it should be easy to do.

I have locked the Allwinner A10 CPU in my Mele A2000 to 60 MHz using cpufreq-set,
and ran your test. rnd.lzo is a 9 MB file from /dev/urandom compressed with lzo.
There doesn't seem to be a significant difference between all three variants.

# time for i in {1..20}; do old/unlzop < rnd.lzo >/dev/null ; done

real	0m11.353s
user	0m3.060s
sys	0m8.170s
# time for i in {1..20}; do new/unlzop < rnd.lzo >/dev/null ; done

real	0m11.416s
user	0m3.030s
sys	0m8.200s
# time for i in {1..20}; do test/unlzop < rnd.lzo >/dev/null ; done

real	0m11.310s
user	0m3.100s
sys	0m8.150s

-- 
With respect,
Roman

~~~~~~~~~~~~~~~~~~~~~~~~~~~
"Stallman had a printer,
with code he could not see.
So he began to tinker,
and set the software free."

Download attachment "signature.asc" of type "application/pgp-signature" (199 bytes)