From: Paul Eggert <eggert@cs.ucla.edu>
To: Andreas Schwab <schwab@linux-m68k.org>
Cc: emacs-devel@gnu.org
Subject: Re: VIRT_ADDR_VARIES
Date: Tue, 08 Nov 2011 09:34:57 -0800 [thread overview]
Message-ID: <4EB96841.7020701@cs.ucla.edu> (raw)
In-Reply-To: <m34nyfkn51.fsf@hase.home>
On 11/08/11 00:56, Andreas Schwab wrote:
> Paul Eggert <eggert@cs.ucla.edu> writes:
>
>> Compiling without VIRT_ADDR_VARIES speeds up aset by 44% on my host
>
> I cannot reproduce that. The difference I get is lost in the noise.
This appears to be weirdness on my end -- my host gives reproducible
results when I use those executables, but when I build them again
I get results showing that VIRT_ADDR_VARIES speeds things up, which
can't be right. I'll try to get to the bottom of this but
for now please ignore my claim about measurable performance difference.
>> Sorry, I don't know the context. What's the bug here?
>
> $ valgrind src/temacs
> [...]
> Segmentation fault
Is that a segmentation fault in valgrind itself, or in temacs?
I don't see why running temacs under valgrind would affect
VIRT_ADDR_VARIES; surely valgrind doesn't change the pure array's
address.
But you're right: if setting VIRT_ADDR_VARIES has no measurable
performance difference and if it lets people debug better, that's
a pretty strong argument for having it always on.
next prev parent reply other threads:[~2011-11-08 17:34 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-06 17:18 VIRT_ADDR_VARIES Andreas Schwab
2011-11-07 1:50 ` VIRT_ADDR_VARIES Paul Eggert
2011-11-07 8:38 ` VIRT_ADDR_VARIES Andreas Schwab
2011-11-07 23:23 ` VIRT_ADDR_VARIES Paul Eggert
2011-11-08 8:56 ` VIRT_ADDR_VARIES Andreas Schwab
2011-11-08 17:34 ` Paul Eggert [this message]
2011-11-08 18:38 ` VIRT_ADDR_VARIES Andreas Schwab
2011-11-08 21:17 ` VIRT_ADDR_VARIES Paul Eggert
2011-11-08 22:06 ` VIRT_ADDR_VARIES Andreas Schwab
2011-11-09 17:44 ` VIRT_ADDR_VARIES Paul Eggert
2011-11-09 21:32 ` VIRT_ADDR_VARIES Andreas Schwab
2011-11-10 8:17 ` VIRT_ADDR_VARIES Paul Eggert
2011-11-10 9:29 ` VIRT_ADDR_VARIES Andreas Schwab
2011-11-10 16:19 ` VIRT_ADDR_VARIES Paul Eggert
2011-11-10 11:06 ` VIRT_ADDR_VARIES Eli Zaretskii
2011-11-10 11:20 ` VIRT_ADDR_VARIES Andreas Schwab
2011-11-10 16:29 ` VIRT_ADDR_VARIES Paul Eggert
2011-11-10 16:43 ` VIRT_ADDR_VARIES Eli Zaretskii
2011-11-10 16:50 ` VIRT_ADDR_VARIES Paul Eggert
2011-11-10 18:06 ` VIRT_ADDR_VARIES Eli Zaretskii
2011-11-14 4:57 ` VIRT_ADDR_VARIES Paul Eggert
2011-11-10 4:05 ` VIRT_ADDR_VARIES Stephen J. Turnbull
2011-11-10 5:40 ` VIRT_ADDR_VARIES Paul Eggert
2011-11-10 17:05 ` VIRT_ADDR_VARIES Andreas Schwab
2011-11-10 17:15 ` VIRT_ADDR_VARIES Paul Eggert
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