* Big kernel size increase with gcc 3.4
@ 2003-08-08 2:39 Bernardo Innocenti
2003-08-08 2:49 ` Aaron Lehmann
2003-08-08 19:24 ` tm_gccmail
0 siblings, 2 replies; 5+ messages in thread
From: Bernardo Innocenti @ 2003-08-08 2:39 UTC (permalink / raw)
To: gcc; +Cc: linux-kernel
Hello,
these figures speak for themselves:
text data bss dec hex filename
833352 47200 78884 959436 ea3cc linux-2.6.x/vmlinux_gcc331
877420 53212 78884 1009516 f676c linux-2.6.x/vmlinux_gcc34
- target is linux-2.6.0-test2-uc0 for m68knommu (full config
available on request);
- same optimization flags: -m5307 -O2 -fno-strict-aliasing
-fno-common -fno-builtin -fomit-frame-pointer
- same ColdFire GCC patches were used (I strongly doubt it
could be a back-end issue);
- gcc-3.3.1-20030720 VS gcc-3.4-20030806.
I can provide more datails if needed. Could be an inlining issue
of course.
Out of curiosity, it seems that the old 2.95.3 could finally be
sent to rest now:
text data bss dec hex filename
833352 47200 78884 959436 ea3cc linux-2.6.x/vmlinux_gcc331
857208 72800 60836 990844 f1e7c linux-2.6.x/vmlinux_gcc295
--
// Bernardo Innocenti - Develer S.r.l., R&D dept.
\X/ http://www.develer.com/
Please don't send Word attachments - http://www.gnu.org/philosophy/no-word-attachments.html
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: Big kernel size increase with gcc 3.4
2003-08-08 2:39 Big kernel size increase with gcc 3.4 Bernardo Innocenti
@ 2003-08-08 2:49 ` Aaron Lehmann
2003-08-08 14:00 ` Bernardo Innocenti
[not found] ` <20030808053327.GZ150921@niksula.cs.hut.fi>
2003-08-08 19:24 ` tm_gccmail
1 sibling, 2 replies; 5+ messages in thread
From: Aaron Lehmann @ 2003-08-08 2:49 UTC (permalink / raw)
To: Bernardo Innocenti; +Cc: gcc, linux-kernel
On Fri, Aug 08, 2003 at 04:39:02AM +0200, Bernardo Innocenti wrote:
> - same optimization flags: -m5307 -O2 -fno-strict-aliasing
> -fno-common -fno-builtin -fomit-frame-pointer
You should try -Os if you want to optimize for size.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: Big kernel size increase with gcc 3.4
2003-08-08 2:49 ` Aaron Lehmann
@ 2003-08-08 14:00 ` Bernardo Innocenti
[not found] ` <20030808053327.GZ150921@niksula.cs.hut.fi>
1 sibling, 0 replies; 5+ messages in thread
From: Bernardo Innocenti @ 2003-08-08 14:00 UTC (permalink / raw)
To: Aaron Lehmann; +Cc: gcc, linux-kernel
Aaron Lehmann wrote:
> On Fri, Aug 08, 2003 at 04:39:02AM +0200, Bernardo Innocenti wrote:
>
>>- same optimization flags: -m5307 -O2 -fno-strict-aliasing
>> -fno-common -fno-builtin -fomit-frame-pointer
>
> You should try -Os if you want to optimize for size.
I did some time ago, and it seems to reduce the code size greatly,
but then I noticed some problems with the memory allocator and
switched back to -O2 for fear that changing the inlining policy
could lead to instability.
I still see those memory allocator problems, so I think I could
safely switch back to -Os now... actually I would recommend it
for all embedded targets.
--
// Bernardo Innocenti - Develer S.r.l., R&D dept.
\X/ http://www.develer.com/
Please don't send Word attachments - http://www.gnu.org/philosophy/no-word-attachments.html
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: Big kernel size increase with gcc 3.4
[not found] ` <20030808053327.GZ150921@niksula.cs.hut.fi>
@ 2003-08-08 15:10 ` Bernardo Innocenti
0 siblings, 0 replies; 5+ messages in thread
From: Bernardo Innocenti @ 2003-08-08 15:10 UTC (permalink / raw)
To: Ville Herva; +Cc: Aaron Lehmann, gcc, linux-kernel
Ville Herva wrote:
>>You should try -Os if you want to optimize for size.
>
> I was about to suggest that, too.
>
> It could be that while optimizing for speed, gcc 3.4 simply inlines way more
> by default (whether or not that actually makes the code faster is a
> different question). I think -Os could be a better comparison.
You were both right. With -Os, GCC 3.3.1 and 3.4 perform
similarly, with a slight advantage for 3.4 :-)
text data bss dec hex filename
833352 47200 78884 959436 ea3cc vmlinux_gcc331
807140 48036 78884 934060 e40ac vmlinux_gcc331_Os
796264 50560 78884 925708 e200c vmlinux_gcc34_Os
--
// Bernardo Innocenti - Develer S.r.l., R&D dept.
\X/ http://www.develer.com/
Please don't send Word attachments - http://www.gnu.org/philosophy/no-word-attachments.html
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: Big kernel size increase with gcc 3.4
2003-08-08 2:39 Big kernel size increase with gcc 3.4 Bernardo Innocenti
2003-08-08 2:49 ` Aaron Lehmann
@ 2003-08-08 19:24 ` tm_gccmail
1 sibling, 0 replies; 5+ messages in thread
From: tm_gccmail @ 2003-08-08 19:24 UTC (permalink / raw)
To: Bernardo Innocenti; +Cc: gcc, linux-kernel
On Fri, 8 Aug 2003, Bernardo Innocenti wrote:
> Hello,
>
> these figures speak for themselves:
>
> text data bss dec hex filename
> 833352 47200 78884 959436 ea3cc linux-2.6.x/vmlinux_gcc331
> 877420 53212 78884 1009516 f676c linux-2.6.x/vmlinux_gcc34
>
>
> - target is linux-2.6.0-test2-uc0 for m68knommu (full config
> available on request);
>
> - same optimization flags: -m5307 -O2 -fno-strict-aliasing
> -fno-common -fno-builtin -fomit-frame-pointer
Could you add -fno-reorder-blocks and report the result?
Toshi
^ permalink raw reply [flat|nested] 5+ messages in thread
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2003-08-08 2:39 Big kernel size increase with gcc 3.4 Bernardo Innocenti
2003-08-08 2:49 ` Aaron Lehmann
2003-08-08 14:00 ` Bernardo Innocenti
[not found] ` <20030808053327.GZ150921@niksula.cs.hut.fi>
2003-08-08 15:10 ` Bernardo Innocenti
2003-08-08 19:24 ` tm_gccmail
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