* Performance regression in CVS HEAD's *compilation* buffer
@ 2009-02-04 3:42 sand
2011-01-29 5:28 ` Stefan Monnier
0 siblings, 1 reply; 4+ messages in thread
From: sand @ 2009-02-04 3:42 UTC (permalink / raw
To: emacs-devel
I updated my CVS tree to HEAD today (2009-02-03, around noon PST),
compiled it, and started using it. My previous sync had been around
2008-12-01. During that interval, the performance of inserting long
lines into the *compilation* buffer has dropped by an order of
magnitude.
Here's a simple test case to reproduce:
* In *scratch*, create 96 lines of "x" characters, 64 characters wide.
<f3> C-u 64 C-u x C-m <f4>
C-u 95 <f4>
* Put them all onto a single line.
M-<
C-u 10000 C-x f
M-q
* Put an "echo" on the front to make it an invokable command, and copy
it to a register.
e c h o <SPC>
C-x h
C-x r x c
* Run `compile' with that command:
M-x compile
C-a C-k
C-x r i c
<RET>
It used to take on the order of 10 seconds to complete. For example,
on my home machine:
-*- mode: compilation; default-directory: "~/" -*-
Compilation started at Tue Feb 3 19:28:40
echo [...]
[...]
Compilation finished at Tue Feb 3 19:28:50
(Output elided.) With CVS HEAD, this takes well over a minute. In
both cases, Emacs is completely unresponsive during this display
period. This is a big problem when running Make with extremely long
(~6kB) output lines.
My home machine is a Debian box running a snapshot of CVS HEAD from
2009-01-11, and I'm unable to reproduce it here, so the performance
drop seems to happened sometime between the 11th and today.
Thanks,
Derek
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Performance regression in CVS HEAD's *compilation* buffer
2009-02-04 3:42 Performance regression in CVS HEAD's *compilation* buffer sand
@ 2011-01-29 5:28 ` Stefan Monnier
2011-01-29 6:24 ` David Kastrup
0 siblings, 1 reply; 4+ messages in thread
From: Stefan Monnier @ 2011-01-29 5:28 UTC (permalink / raw
To: sand; +Cc: emacs-devel
> I updated my CVS tree to HEAD today (2009-02-03, around noon PST),
> compiled it, and started using it. My previous sync had been around
> 2008-12-01. During that interval, the performance of inserting long
> lines into the *compilation* buffer has dropped by an order of
> magnitude.
I've only recently started taking a look at compile.el and haven't had
a chance to investigate this problem, but I just tried:
M-x compile RET echo C-u 6400 x RET
and it finished instantly. Maybe this is because the problem was fixed
a while ago. But I also just installed a change which should
significantly help such cases by only processing lines when they're
complete, which avoids an N^2 behavior.
Stefan
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Performance regression in CVS HEAD's *compilation* buffer
2011-01-29 5:28 ` Stefan Monnier
@ 2011-01-29 6:24 ` David Kastrup
2011-01-29 15:46 ` Stefan Monnier
0 siblings, 1 reply; 4+ messages in thread
From: David Kastrup @ 2011-01-29 6:24 UTC (permalink / raw
To: emacs-devel
Stefan Monnier <monnier@iro.umontreal.ca> writes:
>> I updated my CVS tree to HEAD today (2009-02-03, around noon PST),
>> compiled it, and started using it. My previous sync had been around
>> 2008-12-01. During that interval, the performance of inserting long
>> lines into the *compilation* buffer has dropped by an order of
>> magnitude.
>
> I've only recently started taking a look at compile.el and haven't had
> a chance to investigate this problem, but I just tried:
>
> M-x compile RET echo C-u 6400 x RET
>
> and it finished instantly.
Because that would arrive batched. Try
M-x compile RET echo C-u 6400 x | dd obs=1 RET
--
David Kastrup
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Performance regression in CVS HEAD's *compilation* buffer
2011-01-29 6:24 ` David Kastrup
@ 2011-01-29 15:46 ` Stefan Monnier
0 siblings, 0 replies; 4+ messages in thread
From: Stefan Monnier @ 2011-01-29 15:46 UTC (permalink / raw
To: David Kastrup; +Cc: emacs-devel
>>> I updated my CVS tree to HEAD today (2009-02-03, around noon PST),
>>> compiled it, and started using it. My previous sync had been around
>>> 2008-12-01. During that interval, the performance of inserting long
>>> lines into the *compilation* buffer has dropped by an order of
>>> magnitude.
>> I've only recently started taking a look at compile.el and haven't had
>> a chance to investigate this problem, but I just tried:
>> M-x compile RET echo C-u 6400 x RET
>> and it finished instantly.
> Because that would arrive batched. Try
> M-x compile RET echo C-u 6400 x | dd obs=1 RET
Good point. But I just tried it and it seems to still be "instantaneous".
Stefan
^ permalink raw reply [flat|nested] 4+ messages in thread
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2009-02-04 3:42 Performance regression in CVS HEAD's *compilation* buffer sand
2011-01-29 5:28 ` Stefan Monnier
2011-01-29 6:24 ` David Kastrup
2011-01-29 15:46 ` Stefan Monnier
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