Subject: bug#28149: 26.0.50; Emacs regularly hangs for multiple seconds in e.g. find-file

From: Alexander Asteroth <[email-masked]>
Date: Mon, 21 Aug 2017 09:07:05 +0200

Hi Eli,

I tried and after bisection after bisection, hangs got less but did not
disappear. Then I did one final test with emacs -Q again and actually
managed, after several minutes, a hanging as well, after find-file with
completion in buffers with lots of files in it (/usr/share/... or
similar).

I come to the conclusion, that it probably is not an emacs problem at
all but rather a hardware or OS problem that manifests only in a singe
threaded application like emacs.

... the search continues ...

-- Alex

Eli Zaretskii writes:

>> From: Alexander Asteroth <[email-masked]>
>> Date: Sat, 19 Aug 2017 09:50:44 +0200
>>
>> I suspected the read(4, ....) call since it always appears near the end,
>> but then tried also stracing emacs -Q and a) it does not seem to have
>> the hanging problem and b) it also containes these reads, that take 0.4
>> to 0.9 seconds.
>>
>> Any suggestion how I could narrow down the cause of this problem?
>
> If "emacs" hangs, but "emacs -Q" doesn't, then how about bisecting
> your init file to find the customization(s) that cause these hangs?
>
> One other thing to try is start the profiler (M-x profiler-start), do
> whatever it takes to cause the hang, then type M-x profiler-report,
> expand all the branches in the tree it presents and post the result
> here.  This could give a hint about the package/feature which causes
> this.
>
> Thanks.