emacs is slow while processing a big file

emacs is slow while processing a big file

[Saravanan M D]

I am using emacs-21.3. When i open a big file and navigate through it.
It is very slow even to get to the next page. If i open the same file
with gvim it is faster. what should i do to speed up this.

Thanks,
saravanan


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Re: emacs is slow while processing a big file

[Alan Mackenzie]

Saravanan M D <Saravanan.MD@arm.com> wrote on Thu, 06 Apr 2006 09:55:39
+0530:
> I am using emacs-21.3. When i open a big file and navigate through it.
> It is very slow even to get to the next page. If i open the same file
> with gvim it is faster. what should i do to speed up this.

Well, you could start by telling us a bit more about the file!  What
"mode" was it loaded in, i.e. was it a text file, a C source file, or
what?  How big was it?  Is there anything else noteworthy about the file?

> Thanks,
> saravanan


> IMPORTANT NOTICE: The contents of this email and any attachments are
> confidential and may also be privileged. If you are not the intended
> recipient, please notify the sender immediately and do not disclose the
> contents to any other person, use it for any purpose, or store or copy
> the information in any medium.

Whoops, sorry, too late!  I've actually read your email.  I've actually
stored its contents.  Sorry!

-- 
Alan Mackenzie (Munich, Germany)
Email: aacm@muuc.dee; to decode, wherever there is a repeated letter
(like "aa"), remove half of them (leaving, say, "a").

Re: emacs is slow while processing a big file

[David Kastrup]

Alan Mackenzie <acm@muc.de> writes:

> Saravanan M D <Saravanan.MD@arm.com> wrote on Thu, 06 Apr 2006 09:55:39
> +0530:
>> I am using emacs-21.3. When i open a big file and navigate through it.
>> It is very slow even to get to the next page. If i open the same file
>> with gvim it is faster. what should i do to speed up this.
>
> Well, you could start by telling us a bit more about the file!  What
> "mode" was it loaded in, i.e. was it a text file, a C source file, or
> what?  How big was it?  Is there anything else noteworthy about the file?

I should not be surprised if he was using font-lock-mode.  There is a
reason we did not make it the default for Emacs-21.3.

-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum

Re: emacs is slow while processing a big file

[Saravanan M D]

It is a verilog file (text) and its size is 17MB. The mode is verilog.

Saravanan M D <Saravanan.MD@arm.com> wrote on Thu, 06 Apr 2006 09:55:39 
+0530:

>> I am using emacs-21.3. When i open a big file and navigate through it.
>> It is very slow even to get to the next page. If i open the same file
>> with gvim it is faster. what should i do to speed up this.
>  
>
Well, you could start by telling us a bit more about the file! What 
"mode" was it loaded in, i.e. was it a text file, a C source file, or 
what? How big was it? Is there anything else noteworthy about the file?

>> Thanks,
>> saravanan
>  
>
>> IMPORTANT NOTICE: The contents of this email and any attachments are
>> confidential and may also be privileged. If you are not the intended
>> recipient, please notify the sender immediately and do not disclose the
>> contents to any other person, use it for any purpose, or store or copy
>> the information in any medium.
>  
>
Whoops, sorry, too late! I've actually read your email. I've actually 
stored its contents. Sorry!

Re: emacs is slow while processing a big file

[Rupert Swarbrick]

Saravanan M D wrote:
> It is a verilog file (text) and its size is 17MB. The mode is verilog.
> 

OK. Well, if you read David Kastrup's answer, he points out that if
font-lock is on, things will be slow. So one question is: "Is font-lock
on?" (that's the pretty syntax-colouring) and "Do I need it?".

Surely, you can't be _editing_ a 17mb file?? Is there a way to look at a
smaller bit of it? I believe Emacs loads the whole file when you open
it, so a big file takes a lot of memory - I don't know, but there may be
a package allowing you to view "bits" of a file in memory at one time -
anyone? As verilog's syntax is simple, a truncation probably wouldn't
confuse the mode very much either.

Finally, and slightly off-topic, PLEASE don't top post. It really is
very irritating.

Good luck anyway,

Rupert

Re: emacs is slow while processing a big file

[Reiner Steib]

On Thu, Apr 06 2006, Rupert Swarbrick wrote:

> OK. Well, if you read David Kastrup's answer, he points out that if
> font-lock is on, things will be slow. So one question is: "Is font-lock
> on?" (that's the pretty syntax-colouring) and "Do I need it?".

,----[ <f1> v font-lock-maximum-size RET ]
| font-lock-maximum-size is a variable defined in `font-lock.el'.
| Its value is 256000
| 
| Documentation:
| *Maximum size of a buffer for buffer fontification.
| Only buffers less than this can be fontified when Font Lock mode is turned on.
| If nil, means size is irrelevant.
| [...]
`----

The default in Emacs 21 is 256000 too.

Bye, Reiner.
-- 
       ,,,
      (o o)
---ooO-(_)-Ooo---  |  PGP key available  |  http://rsteib.home.pages.de/

Re: emacs is slow while processing a big file

[Stefan Monnier]

> | font-lock-maximum-size is a variable defined in `font-lock.el'.
[...]
> The default in Emacs 21 is 256000 too.

And this variable is ignored if you use jit-lock, as is the case by default
in Emacs-21.


        Stefan

Re: emacs is slow while processing a big file

[Reiner Steib]

On Thu, Apr 06 2006, Stefan Monnier wrote:

>> | font-lock-maximum-size is a variable defined in `font-lock.el'.
> [...]
>> The default in Emacs 21 is 256000 too.
>
> And this variable is ignored if you use jit-lock, as is the case by default
> in Emacs-21.

Is there some other limit for jit-lock?  I recall that for a colleague
if mine, font-locking stopped in his thesis (LaTeX mode) when the file
size reached some limit.  I think he was using Emacs 21 (surely not
Emacs 22), but maybe it was Emacs 20.7.

Bye, Reiner.
-- 
       ,,,
      (o o)
---ooO-(_)-Ooo---  |  PGP key available  |  http://rsteib.home.pages.de/