LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: "Rogério Brito" <rbrito@ime.usp.br>
To: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org,
	akpm@linux-foundation.org
Subject: Re: [PATCH] powerpc: compile kernel for linkstations optimized for size
Date: Mon, 13 Oct 2008 19:28:02 -0200	[thread overview]
Message-ID: <BAFAB2E9-A9E1-443D-9774-459965AF52C1@ime.usp.br> (raw)
In-Reply-To: <Pine.LNX.4.64.0810131959140.9041@axis700.grange>

Hi, Guennadi.

On 13/10/2008, at 16:03, Guennadi Liakhovetski wrote:

> On Mon, 13 Oct 2008, Rogério Brito wrote:
>
>> From: Rogério Brito <rbrito@ime.usp.br>
>>
>> Since Linkstations and Kuroboxes often have *very* little memory (as
>> they are embedded systems), it is desirable to get their kernels
>> compiled optimized for size.
>>
>> Signed-off-by: Rogério Brito <rbrito@ime.usp.br>
>>
>> ---
>>
>> I have been using kernels optimized for size on my Kurobox (standard)
>> for many different releases and I have experienced no problem with  
>> this
>> option enabled. Thus, this patch.
>
> The comment for this option says: "watch out for broken compilers," if
> this doesn't hold any more, it should be remove, if it still holds, I
> wouldn't turn this on by default, as I don't think we can test all

Pragmatically speaking, -O2 can be broken too (and see the amount of  
ICEs that you can get with newer kernels even compiling with -O2).  
Unless you prove that the compiler is correct and keeps all its  
invariants, then you can rely on this. But, pragmatically speaking  
again, gcc has bugs.

But leaving the mathematical situation aside (Dijkstra would have  
spanked all of us here :)), as I mentioned below the signed off line,  
I have been using -Os and it is working fine. It's serving me quite  
well and with a decent uptime:

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -  
- - -
lutz:~# uptime
  19:22:53 up 17 days,  5:56,  1 user,  load average: 0.00, 0.00, 0.00
lutz:~# uname -a
Linux lutz 2.6.27-rc6.try02 #8 Fri Sep 26 11:29:55 BRT 2008 ppc GNU/ 
Linux
lutz:~#
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -  
- - -

And, despite the 0.00 load, I'm streaming music with it via mt-daapd  
and serving cifs mounts.

> possible (cross- or native-) compilers users might want to use. In any
> case this is one of options that users can select themselves, if it  
> suits
> them.

And that is, not to mention, with a very home-brew and quick'n'dirty  
cross-compiled kernel (with a vanilla gcc 4.2.0 taken straight from  
gcc.gnu.org; the same with the kernel: no patches applied).

-- 
Rogério Brito : rbrito@{mackenzie,ime.usp}.br : GPG key 1024D/7C2CAEB8
http://www.ime.usp.br/~rbrito : http://meusite.mackenzie.com.br/rbrito
Projects: algorithms.berlios.de : lame.sf.net : vrms.alioth.debian.org




  reply	other threads:[~2008-10-13 21:28 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-10-13  4:07 Rogério Brito
2008-10-13  4:51 ` [PATCH] powerpc: enable heap randomization for linkstations Rogério Brito
2008-10-13 18:05   ` Guennadi Liakhovetski
2008-10-13 18:44     ` Scott Wood
2008-10-13 19:27       ` Guennadi Liakhovetski
2008-10-13 20:56       ` Rogério Brito
2008-10-19  2:53       ` Rogério Brito
2008-10-19  3:16         ` Rogério Brito
2008-10-17  9:38   ` Rogério Brito
2008-10-28 13:58   ` Kumar Gala
2008-10-13 18:03 ` [PATCH] powerpc: compile kernel for linkstations optimized for size Guennadi Liakhovetski
2008-10-13 21:28   ` Rogério Brito [this message]
2008-10-17  9:37 ` Rogério Brito
2008-10-28 13:58 ` Kumar Gala

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=BAFAB2E9-A9E1-443D-9774-459965AF52C1@ime.usp.br \
    --to=rbrito@ime.usp.br \
    --cc=akpm@linux-foundation.org \
    --cc=g.liakhovetski@gmx.de \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linuxppc-dev@ozlabs.org \
    --subject='Re: [PATCH] powerpc: compile kernel for linkstations optimized for size' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).