Emacs cvs (23) uses too much CPU with compilation mode

Emacs cvs (23) uses too much CPU with compilation mode

[Felipe Magno de Almeida]

Hi,

I can see emacs uses 80% of CPU of a 600Mhz Celeron for about 2
minutes after it gets the compiler error output.
The compiler only runs for less than 15 seconds.
It happens only when the error message is a bit big. ( > 50Kb).
It is instantaneous with emacs-22.3. I don't have to wait at all.
I'm using multi-tty, but I can reproduce it without server-start. I
also use CEDET, but
the behavior is the same without it.
Sometimes the error message is *much bigger*. And that makes it
unbearable to wait.
Is this behavior known? Is it considered a bug? Is there anything I
can do (aside from not using compilation
mode, or using emacs v22.3)?

Both emacs (emacs-23 and emacs-22.3 are compiled for console and used
through ssh).

-- 
Felipe Magno de Almeida

Re: Emacs cvs (23) uses too much CPU with compilation mode

[Felipe Magno de Almeida]

On Thu, Apr 16, 2009 at 6:28 PM, Felipe Magno de Almeida
<felipe.m.almeida@gmail.com> wrote:
> Hi,
>
> I can see emacs uses 80% of CPU of a 600Mhz Celeron for about 2
> minutes after it gets the compiler error output.
> The compiler only runs for less than 15 seconds.
> It happens only when the error message is a bit big. ( > 50Kb).
> It is instantaneous with emacs-22.3. I don't have to wait at all.
> I'm using multi-tty, but I can reproduce it without server-start. I
> also use CEDET, but
> the behavior is the same without it.
> Sometimes the error message is *much bigger*. And that makes it
> unbearable to wait.
> Is this behavior known? Is it considered a bug? Is there anything I
> can do (aside from not using compilation
> mode, or using emacs v22.3)?
>
> Both emacs (emacs-23 and emacs-22.3 are compiled for console and used
> through ssh).

ping?

> --
> Felipe Magno de Almeida


-- 
Felipe Magno de Almeida

Re: Emacs cvs (23) uses too much CPU with compilation mode

[Nikolaj Schumacher]

> On Thu, Apr 16, 2009 at 6:28 PM, Felipe Magno de Almeida
> <felipe.m.almeida@gmail.com> wrote:
>> Hi,
>>
>> I can see emacs uses 80% of CPU of a 600Mhz Celeron for about 2
>> minutes after it gets the compiler error output.
>> The compiler only runs for less than 15 seconds.
>> It happens only when the error message is a bit big. ( > 50Kb).
>> It is instantaneous with emacs-22.3. I don't have to wait at all.
>> I'm using multi-tty, but I can reproduce it without server-start. I
>> also use CEDET, but
>> the behavior is the same without it.
>> Sometimes the error message is *much bigger*. And that makes it
>> unbearable to wait.

Here's a guess:  The compilation buffer gets fontified.

Either fontification (and setting error markers) takes longer in Emacs
23, or just the progress messages for fontification (because drawing
antialiased fonts is slower).

Test by disabling `font-lock-mode', or setting `font-lock-verbose' to nil.


regards,
Nikolaj Schumacher

Re: Emacs cvs (23) uses too much CPU with compilation mode

[Nikolaj Schumacher]

On 2009-05-12, at 13:43, Felipe Magno de Almeida wrote:
> Thanks,
> I was starting to get worried my messages weren't getting through.

No, we just didn't have a clue what is going on.
(Please CC the list in your answers. I likely can't answer all your  
questions

>> Either fontification (and setting error markers) takes longer in  
>> Emacs
>> 23, or just the progress messages for fontification (because drawing
>> antialiased fonts is slower).
>>
>> Test by disabling `font-lock-mode', or setting `font-lock-verbose'  
>> to nil.
>
> It is by ssh. In console.
> I don't think (?) there's any fontification for console.

Fontification is the emacs expression for adding text properties like  
color. Even if your terminal doesn't display the color, Emacs will  
produce it in the background, because the links in the compilation  
buffer are created in the same process.

Re: Emacs cvs (23) uses too much CPU with compilation mode

[Felipe Magno de Almeida]

On Tue, May 12, 2009 at 8:48 AM, Nikolaj Schumacher <me@nschum.de> wrote:
> On 2009-05-12, at 13:43, Felipe Magno de Almeida wrote:
>>

Hi Nikolaj,

>>> Test by disabling `font-lock-mode', or setting `font-lock-verbose' to
>>> nil.
>>
>> It is by ssh. In console.
>> I don't think (?) there's any fontification for console.
>
> Fontification is the emacs expression for adding text properties like color.
> Even if your terminal doesn't display the color, Emacs will produce it in
> the background, because the links in the compilation buffer are created in
> the same process.

I see, I've tried both. It is still very slow. The emacs23 with GTK+
in another more powerful machine is also a lot slower in compilation
mode than emacs22.
But since the machine is much more powerful. It doesn't quite bother me much.
But this celeron 600 gets unbearable with huge error messages.

-- 
Felipe Magno de Almeida

Re: Emacs cvs (23) uses too much CPU with compilation mode

[daviddisco]

On May 8, 9:39 pm, Felipe Magno de Almeida
<felipe.m.alme...@gmail.com> wrote:
> On Thu, Apr 16, 2009 at 6:28 PM, Felipe Magno de Almeida
>
>
>
> <felipe.m.alme...@gmail.com> wrote:
> > Hi,
>
> > I can see emacs uses 80% of CPU of a 600Mhz Celeron for about 2
> > minutes after it gets the compiler error output.
> > The compiler only runs for less than 15 seconds.
> > It happens only when the error message is a bit big. ( > 50Kb).
> > It is instantaneous with emacs-22.3. I don't have to wait at all.
> > I'm using multi-tty, but I can reproduce it without server-start. I
> > also use CEDET, but
> > the behavior is the same without it.
> > Sometimes the error message is *much bigger*. And that makes it
> > unbearable to wait.
> > Is this behavior known? Is it considered a bug? Is there anything I
> > can do (aside from not using compilation
> > mode, or using emacs v22.3)?
>
> > Both emacs (emacs-23 and emacs-22.3 are compiled for console and used
> > through ssh).
>
> ping?
>
> > --
> > Felipe Magno de Almeida
>
> --
> Felipe Magno de Almeida

Check the value of compilation-error-regexp-alist.  Remove any
unnecessary regular expressions.  It might help.

Re: Emacs cvs (23) uses too much CPU with compilation mode

[jvc]

> Check the value of compilation-error-regexp-alist.  Remove any
> unnecessary regular expressions.  It might help.

This fixed it for me. Thanks!