* More __get_user_asm_ll32 ...
@ 2007-02-13 13:32 Ralf Baechle
2007-02-13 16:06 ` Atsushi Nemoto
0 siblings, 1 reply; 3+ messages in thread
From: Ralf Baechle @ 2007-02-13 13:32 UTC (permalink / raw)
To: Franck Bui-Huu; +Cc: linux-mips
__get_user_asm_ll32 contains a junk move %0, $0 left over from an older
version of the code. Ignoring fixups code and data this instruction
inflates the normal path in __get_user() by 50% which may explain much of
the size and performance you have meassures. It also always clears
the error return, iow. __get_user_asm_ll32(..., &<something 64-bit>)
would never have returned an error. ARGH.
Ralf
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: More __get_user_asm_ll32 ...
2007-02-13 13:32 More __get_user_asm_ll32 Ralf Baechle
@ 2007-02-13 16:06 ` Atsushi Nemoto
2007-02-13 16:11 ` Ralf Baechle
0 siblings, 1 reply; 3+ messages in thread
From: Atsushi Nemoto @ 2007-02-13 16:06 UTC (permalink / raw)
To: ralf; +Cc: vagabon.xyz, linux-mips
On Tue, 13 Feb 2007 13:32:51 +0000, Ralf Baechle <ralf@linux-mips.org> wrote:
> __get_user_asm_ll32 contains a junk move %0, $0 left over from an older
> version of the code. Ignoring fixups code and data this instruction
> inflates the normal path in __get_user() by 50% which may explain much of
> the size and performance you have meassures. It also always clears
> the error return, iow. __get_user_asm_ll32(..., &<something 64-bit>)
> would never have returned an error. ARGH.
Why is it clears the error return? The "3:" label is just after the
junk move.
---
Atsushi Nemoto
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: More __get_user_asm_ll32 ...
2007-02-13 16:06 ` Atsushi Nemoto
@ 2007-02-13 16:11 ` Ralf Baechle
0 siblings, 0 replies; 3+ messages in thread
From: Ralf Baechle @ 2007-02-13 16:11 UTC (permalink / raw)
To: Atsushi Nemoto; +Cc: vagabon.xyz, linux-mips
On Wed, Feb 14, 2007 at 01:06:15AM +0900, Atsushi Nemoto wrote:
> Why is it clears the error return? The "3:" label is just after the
> junk move.
You're right and the final commit message reflects that. So this is really
only a code size (320 bytes) and performance fix.
Ralf
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2007-02-13 16:11 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
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2007-02-13 13:32 More __get_user_asm_ll32 Ralf Baechle
2007-02-13 16:06 ` Atsushi Nemoto
2007-02-13 16:11 ` Ralf Baechle
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