bug#20611: 24.4; mutt slow in ansi-term

[Alexis]

Eli Zaretskii <eliz@gnu.org> writes:

> Do you also see that Emacs 23 is significantly faster?

i wasn't sure which version of 23 i should try, so i downloaded 
both 23.1 and 23.4.

`configure' for 23.1 ran successfully, but compilation failed:

$ make cd lib-src; make all                            \ 
 CC='gcc' CFLAGS='-g -O2 -Wno-pointer-sign ' 
 CPPFLAGS='-D_BSD_SOURCE  ' \ LDFLAGS='-Wl,-znocombreloc ' 
 MAKE='make' 
make[1]: Entering directory 
'/home/alexis/Downloads/src/emacs-23.1/lib-src' Makefile:144: *** 
recipe commences before first target.  Stop.  make[1]: Leaving 
directory '/home/alexis/Downloads/src/emacs-23.1/lib-src' 
Makefile:325: recipe for target 'lib-src' failed make: *** 
[lib-src] Error 2 

`configure' for 23.4 required me to call `configure' with the 
option "--with-crt-dir=/usr/lib/x86_64-linux-gnu". Compilation was 
then successful. This version showed no lag at all.

(However, the alsamixer UI was severely broken, visually - 
excessive line length resulted in line wrapping and blocks of 
white background alternating with blocks of black background, as 
per the attached PNG.) 

> Also, were v24.5 and the current master compiled with the same 
> compilation options, and similar to Emacs 23?

Not according to the following, no. Having said that, i've not 
manually made any modifications to the configuration in the 
tarballs, or on master.

23.4:

CC='gcc' CFLAGS='-g -O2 -Wdeclaration-after-statement 
-Wno-pointer-sign' CPPFLAGS='-D_BSD_SOURCE  ' 
LDFLAGS='-Wl,-znocombreloc  ' MAKE='make'

24.5:

CC='gcc -std=gnu99' CFLAGS='-g3 -O2' CPPFLAGS='' LDFLAGS='' 
MAKE='make'

As for master, the env variables are no longer shown by the 'make' 
process. However, running `make -n' produced lines like:

gcc -std=gnu11 -DHAVE_CONFIG_H -I. -I../lib -I../src -I../src -g3 
-O2 -MT allocator.o -MD -MP -MF .deps/allocator.Tpo -c -o 
allocator

Is that okay? Or can i find better information elsewhere?

> Thanks.  I reviewed all the functions that are high on the 
> profile (term-goto seems to be the main culprit), and didn't see 
> any significant changes in them since Emacs 23.  Some of them 
> were not changed at all.  So I'm puzzled how can Emacs 24 and 
> Emacs 25 be significantly slower only in term.el.

Fair enough. One observation, though: the OP and i are both 
running Debian Jessie.

emacs_23-4.png
Description: PNG image