bug#6116: Emacs 23 is sluggish with Consolas font

bug#6116: Emacs 23 is sluggish with Consolas font

[Vegard Øye]

I use 23.1.1 (i386-mingw-nt5.1.2600) of 2009-07-30 on Windows XP.
My font of choice is Consolas, which was originally released with
Windows Vista, but can be downloaded from the URL below.

Since I moved from 22.3 to 23.1, Emacs has become noticeably slower,
particularly when scrolling. The problems vanish when I select any
other font than Consolas.

WITHOUT CONSOLAS: My .emacs consists of the following two lines.

        (setq scroll-step 1)
        ;; (set-frame-font "Consolas-11")

When I start up Emacs, the font is Courier New. I open the tutorial
with C-h t and hold down C-n until the cursor reaches the bottom of
the screen. When it does, the text scrolls smoothly.

WITH CONSOLAS: I uncomment the second line and start Emacs anew.

        (setq scroll-step 1)
        (set-frame-font "Consolas-11")

Now C-n doesn't scroll at all. Instead, the cursor is repeatedly
recentered each time it reaches the bottom of the screen.

If display-intensive packages like hl-line-mode and show-paren-mode
are loaded as well, Emacs slows to a crawl.

WITH OTHER FONTS: No problems with Lucida Console!

        (setq scroll-step 1)
        (set-frame-font "Lucida Console-11")

This is just as responsive as the default of Courier New.

DOWNLOAD: Consolas is included with Windows Vista and Windows 7.
Otherwise, an .exe installer is available from the address below.
If this is unpractical, mail me and we'll figure out something.

http://www.microsoft.com/downloads/details.aspx?familyid=22e69ae4-7e40-4807-8a86-b3d36fab68d3

Vegard 		 	   		  
_________________________________________________________________
Windows 7: Du får hjelp til gjøre mer. Utforsk Windows 7.
http://windows.microsoft.com/windows-7

bug#6116: Emacs 23 is sluggish with Consolas font

[Christoph]

I followed the recipe above and can confirm the same behavior for Emacs
24.0.50 (r100832) on Windows 7.

Maybe the performance difference is due to Consolas being optimized for
ClearType, whereas the regular Courier New is not?

Christoph

bug#6116: Emacs 23 is sluggish with Consolas font

[Óscar Fuentes]

I cannot reproduce this bug on Windows 7 with

GNU Emacs 24.0.50.1 (i386-mingw-nt6.1.7600) of 2010-07-03

bug#6116: Emacs 23 is sluggish with Consolas font

[James Cloos]

>>>>> "C" == Christoph  <cschol2112@googlemail.com> writes:

C> I followed the recipe above and can confirm the same behavior for Emacs
C> 24.0.50 (r100832) on Windows 7.

C> Maybe the performance difference is due to Consolas being optimized for
C> ClearType, whereas the regular Courier New is not?

It is more likely to do with each fonts' set of OpenType features.
Consolas almost certainly has significantly better OpenType support
than the much older versions of Courier New MS ships.

Perhaps something involving localized forms?

You also may have some system-level feature enabled, perhaps related to
locale, i18n or the like which resutls in slower itf processing?  (That
or something like that might explain why Óscar was unable to duplicate.)

I only have thought, no solutions, but I've read numerous complaints
elsewhere over the recent years which tracked down to inefficient
implementations of OpenType, and that seems to be the most significant
difference between Courier New and Consolas.

-JimC
-- 
James Cloos <cloos@jhcloos.com>         OpenPGP: 1024D/ED7DAEA6

bug#6116: Emacs 23 is sluggish with Consolas font

[Christoph]

On 7/18/2010 1:32 AM, James Cloos wrote:

> It is more likely to do with each fonts' set of OpenType features.
> Consolas almost certainly has significantly better OpenType support
> than the much older versions of Courier New MS ships.

It is Consolas that is more sluggish, not Courier New.

> You also may have some system-level feature enabled, perhaps related to
> locale, i18n or the like which resutls in slower itf processing?  (That
> or something like that might explain why Óscar was unable to duplicate.)

As far as I can tell Óscar and I are using the same system (Windows 7). 
My locale is US. Maybe Óscar can tell us what he is using and whether 
switching to locale US makes it worse?

Christoph

bug#6116: Emacs 23 is sluggish with Consolas font

[Óscar Fuentes]

Christoph <cschol2112@googlemail.com> writes:

> On 7/18/2010 1:32 AM, James Cloos wrote:
>
>> You also may have some system-level feature enabled, perhaps related to
>> locale, i18n or the like which resutls in slower itf processing?  (That
>> or something like that might explain why Óscar was unable to duplicate.)
>
> As far as I can tell Óscar and I are using the same system (Windows
> 7). My locale is US. Maybe Óscar can tell us what he is using and
> whether switching to locale US makes it worse?

I'm using a pristine Windows 7 64bits US install on a virtual
machine. Switching to Spanish makes no difference.

bug#6116: Emacs 23 is sluggish with Consolas font

[Christoph]

On 7/18/2010 8:37 AM, Óscar Fuentes wrote:

> I'm using a pristine Windows 7 64bits US install on a virtual
> machine. Switching to Spanish makes no difference.

Same here, minus the virtual machine.

Did you set scroll-step to 1?

bug#6116: Emacs 23 is sluggish with Consolas font

[Óscar Fuentes]

Christoph <cschol2112@googlemail.com> writes:

> On 7/18/2010 8:37 AM, Óscar Fuentes wrote:
>
>> I'm using a pristine Windows 7 64bits US install on a virtual
>> machine. Switching to Spanish makes no difference.
>
> Same here, minus the virtual machine.
>
> Did you set scroll-step to 1?

Yes.

bug#6116: Emacs 23 is sluggish with Consolas font

[Christoph]

On 7/18/2010 8:56 AM, Óscar Fuentes wrote:
> Christoph<cschol2112@googlemail.com>  writes:
>
>> On 7/18/2010 8:37 AM, Óscar Fuentes wrote:
>>
>>> I'm using a pristine Windows 7 64bits US install on a virtual
>>> machine. Switching to Spanish makes no difference.
>>
>> Same here, minus the virtual machine.
>>
>> Did you set scroll-step to 1?
>
> Yes.

I tried this again.

Setting the font size to 11 and not resizing the window after startup 
(i.e. 38x80), I don't see it either.

If I maximize the screen vertically to 56x80, it does happen.

However, turning off Consolas (and switching to Courier New) and 
maximizing vertically it does happen too, but maybe not as often.

It seems to be a general redisplay problem, if the screen area to be 
redrawn exceeds a certain size.

I initially only tested this with my .emacs configuration, but it does 
the same with `emacs -Q'.

bug#6116: Emacs 23 is sluggish with Consolas font

[Óscar Fuentes]

Christoph <cschol2112@googlemail.com> writes:

> I tried this again.
>
> Setting the font size to 11 and not resizing the window after startup
> (i.e. 38x80), I don't see it either.
>
> If I maximize the screen vertically to 56x80, it does happen.
>
> However, turning off Consolas (and switching to Courier New) and
> maximizing vertically it does happen too, but maybe not as often.
>
> It seems to be a general redisplay problem, if the screen area to be
> redrawn exceeds a certain size.
>
> I initially only tested this with my .emacs configuration, but it does
> the same with `emacs -Q'.

I just tried this:

runemacs -Q
M-x eval-expression ENTER (setq scroll-step 1) ENTER
<maximize the frame vertically>
C-h t
C-n ...

it occasionally recenters, but never gets stuck as described on the
original report. It doesn't matter if I use Courier New or Consolas.

bug#6116: Emacs 23 is sluggish with Consolas font

[Christoph]

On 7/18/2010 9:51 AM, Óscar Fuentes wrote:

> I just tried this:
>
> runemacs -Q
> M-x eval-expression ENTER (setq scroll-step 1) ENTER
> <maximize the frame vertically>
> C-h t
> C-n ...
>
> it occasionally recenters, but never gets stuck as described on the
> original report. It doesn't matter if I use Courier New or Consolas.

I decreased the Consolas font-size to 9 (from 11) and maximized 
vertically (72x80). Now, I can see it being stuck once in a while. It 
recovers eventually but there are a couple of seconds where it seems 
nothing happens. After that it recenters and scrolls on until it happens 
again.

bug#6116: Emacs 23 is sluggish with Consolas font

[Lars Ingebrigtsen]

Christoph <cschol2112@googlemail.com> writes:

> I decreased the Consolas font-size to 9 (from 11) and maximized
> vertically (72x80). Now, I can see it being stuck once in a while. It 
> recovers eventually but there are a couple of seconds where it seems
> nothing happens. After that it recenters and scrolls on until it
> happens again.

Are you still seeing these problems in modern versions of Emacs?

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#6116: Emacs 23 is sluggish with Consolas font

[Stefan Kangas]

Lars Ingebrigtsen <larsi@gnus.org> writes:

> Christoph <cschol2112@googlemail.com> writes:
>
>> I decreased the Consolas font-size to 9 (from 11) and maximized
>> vertically (72x80). Now, I can see it being stuck once in a while. It 
>> recovers eventually but there are a couple of seconds where it seems
>> nothing happens. After that it recenters and scrolls on until it
>> happens again.
>
> Are you still seeing these problems in modern versions of Emacs?

More information was requested, but none was given within 25 weeks, so
I'm closing this bug.

If this is still an issue, please reply to this email (use "Reply to
all" in your email client) and we can reopen the bug report.

Best regards,
Stefan Kangas