From: kyungsik.lee@lge.com (Kyungsik Lee)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v3 -next 3/5] arm: Add support for LZ4-compressed kernel
Date: Fri, 3 May 2013 18:02:52 +0900 [thread overview]
Message-ID: <20130503090252.GB3170@Corona> (raw)
In-Reply-To: <20130430135602.2aa0d3b4ec392bf83a9b64d0@linux-foundation.org>
On Tue, Apr 30, 2013 at 01:56:02PM -0700, Andrew Morton wrote:
> On Tue, 5 Mar 2013 20:47:34 +0900 Kyungsik Lee <kyungsik.lee@lge.com> wrote:
>
> > This patch integrates the LZ4 decompression code to the arm pre-boot code.
> > And it depends on two patchs below
> >
> > lib: Add support for LZ4-compressed kernel
> > decompressor: Add LZ4 decompressor module
> >
> > ...
> >
> > - Apply CFLAGS, -Os to decompress.o to improve decompress
> > performance during boot-up process
> >
> > ...
> >
> > --- a/arch/arm/boot/compressed/Makefile
> > +++ b/arch/arm/boot/compressed/Makefile
> > @@ -24,6 +24,9 @@ endif
> > AFLAGS_head.o += -DTEXT_OFFSET=$(TEXT_OFFSET)
> > HEAD = head.o
> > OBJS += misc.o decompress.o
> > +ifeq ($(CONFIG_KERNEL_LZ4),y)
> > +CFLAGS_decompress.o := -Os
> > +endif
>
> Surprised. You found that -Os produces faster code than -O2? Details,
> please?
-Os is enforced here, based on the test result of decompression time
below, slightly faster than -O2.
But further tests with UA show that using -O2 will be the right choice
especially in the case of the unaligned access enabled.
Decompression Time(counts)
UA
-Os 6717 3447
-O2 6720 2728
Note: ARM v7, Kernel 3.4
counter freq. = 32768 HZ
UA(Unaligned Access)
gcc version 4.6.2 (Ubuntu/Linaro 4.6.2-14ubuntu2~ppa1)
Thanks,
Kyungsik
next prev parent reply other threads:[~2013-05-03 9:02 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-05 11:47 [PATCH v3 -next 0/5] Add support for LZ4-compressed kernel Kyungsik Lee
2013-03-05 11:47 ` [PATCH v3 -next 1/5] decompressor: Add LZ4 decompressor module Kyungsik Lee
2013-03-05 11:47 ` [PATCH v3 -next 2/5] lib: Add support for LZ4-compressed kernel Kyungsik Lee
2013-03-05 11:47 ` [PATCH v3 -next 3/5] arm: " Kyungsik Lee
2013-04-30 20:56 ` Andrew Morton
2013-05-03 9:02 ` Kyungsik Lee [this message]
2013-03-05 11:47 ` [PATCH v3 -next 4/5] x86: " Kyungsik Lee
2013-03-05 16:13 ` H. Peter Anvin
2013-03-06 6:37 ` Kyungsik Lee
2013-04-25 22:43 ` Andrew Morton
2013-03-05 11:47 ` [PATCH v3 -next 5/5] Kconfig: Make x86 and arm kernels default to the LZ4-compressed Kyungsik Lee
2013-03-05 11:58 ` Borislav Petkov
2013-03-05 12:04 ` Florian Fainelli
2013-03-05 23:08 ` Andrew Morton
2013-03-06 9:57 ` Florian Fainelli
2013-03-06 11:16 ` Borislav Petkov
2013-03-05 16:13 ` H. Peter Anvin
2013-03-05 23:06 ` [PATCH v3 -next 0/5] Add support for LZ4-compressed kernel Andrew Morton
2013-03-06 6:15 ` Kyungsik Lee
2013-03-08 6:39 ` Kyungsik Lee
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