Odd slowness in grep and dired modes

Odd slowness in grep and dired modes

[Smith_RS]

This is for NT Emacs 24.3.1 running on Windows 7.

I found a situation where NT Emacs will slow to a crawl and consume high CPU cycles, the common behavior is directory browsing in dired or file browsing in grep-mode where the mouse-over behavior is being used. I ran the profiler and saw that all the time is spent in mouse-fixup-help-message.

Steps to duplicate:

- Open dired on a directory with a non trivial number of files (20 or more).
- Run the mouse over the files without selecting anything, just let the mouse-over behavior happen.
- Do this with profiling turned on and observe thousands of calls to mouse-fixup-help-message.

Alternately:

- Use grep-mode to search for a string that occurs in a large number of files.
- Continue as above.

I ran with Procmon, there is no specific I/O or registry activity during this slowness that I can trace.

I tried this under Linux, I see the calls to mouse-fixup-help-message but it doesn't jack the CPU like on Windows.

Any thoughts or ways to debug this are appreciated, as always.

Thanks.

Re: Odd slowness in grep and dired modes

[Eli Zaretskii]

> Date: Thu, 20 Mar 2014 23:10:52 -0700 (PDT)
> From: Smith_RS <rsmithpv@gmail.com>
> 
> This is for NT Emacs 24.3.1 running on Windows 7.
> 
> I found a situation where NT Emacs will slow to a crawl and consume high CPU cycles, the common behavior is directory browsing in dired or file browsing in grep-mode where the mouse-over behavior is being used. I ran the profiler and saw that all the time is spent in mouse-fixup-help-message.
> 
> Steps to duplicate:
> 
> - Open dired on a directory with a non trivial number of files (20 or more).
> - Run the mouse over the files without selecting anything, just let the mouse-over behavior happen.
> - Do this with profiling turned on and observe thousands of calls to mouse-fixup-help-message.
> 
> Alternately:
> 
> - Use grep-mode to search for a string that occurs in a large number of files.
> - Continue as above.

What exactly "slows to a crawl" in these situations?

I tried the first scenario, in a very large directory, and all I could
see that moving the mouse constantly over the file names makes a
single execution unit occupied by 27%.  I see no particular slow-down,
but since Emacs does nothing but display tooltips, I'm not sure what
operations would be slow in this scenario.

mouse-fixup-help-message generates the text for the tooltip shown when
you have the mouse above the file name, so it is called whenever you
move the mouse to another file.

Re: Odd slowness in grep and dired modes

[Smith_RS]

On Friday, March 21, 2014 1:13:06 AM UTC-7, Eli Zaretskii wrote:
> What exactly "slows to a crawl" in these situations?

I trace Emacs using Process Explorer, on a machine with 4 available cores I see 25% utilization which (to my understanding) means it's at 100% on that core. It takes as long as 30 seconds to a minute to catch up.

If I do a non-trivial grep, my attempts to select files out of the grep results creates enough lag to make the selection process not usable.

Even when I do all the things to turn off tooltips it doesn't stop the behavior. I've tried these:

(setq tooltip-mode nil)
(setq show-help-function nil)

If there were a way to intercept the call to mouse-fixup-help-message so that it just does a "no-op" that would solve this for me.

Re: Odd slowness in grep and dired modes

[Eli Zaretskii]

> Date: Fri, 21 Mar 2014 01:25:46 -0700 (PDT)
> From: Smith_RS <rsmithpv@gmail.com>
> Injection-Date: Fri, 21 Mar 2014 08:25:46 +0000
> 
> On Friday, March 21, 2014 1:13:06 AM UTC-7, Eli Zaretskii wrote:
> > What exactly "slows to a crawl" in these situations?
> 
> I trace Emacs using Process Explorer, on a machine with 4 available cores I see 25% utilization which (to my understanding) means it's at 100% on that core. It takes as long as 30 seconds to a minute to catch up.

Nothing similar is seen on my system.

> If I do a non-trivial grep, my attempts to select files out of the grep results creates enough lag to make the selection process not usable.

Sorry, I don't understand: lag between which events?

> Even when I do all the things to turn off tooltips it doesn't stop the behavior.

Which means the mouse-fixup-help-message is a red herring.  Some other
factor is at work here.

Did this start lately?  If so, what changed around the time this
started happening?

Also, does this happen in "emacs -Q"?  If not, I'd suspect some
customization you have on your .emacs init file.

RE: Odd slowness in grep and dired modes

[Drew Adams]

> If there were a way to intercept the call to mouse-fixup-help-message so
> that it just does a "no-op" that would solve this for me.

If `mouse-fixup-help-message' is the problem, just say no to it:
Do yourself a favor and customize `mouse-1-click-follows-link' to nil.
(Just one opinion.)

Re: Odd slowness in grep and dired modes

[Smith_RS]

On Friday, March 21, 2014 1:57:07 AM UTC-7, Eli Zaretskii wrote:
> Sorry, I don't understand: lag between which events?

Both dired and grep-find give you a list of targets that you can select via mouse-1 or mouse-2, which causes the target file to open in another window. While this list is active you can mouse-over the targets and Emacs will change the face from the default face to the highlighted face, this is the part that's slowing down.

> Did this start lately?  If so, what changed around the time this
> started happening?

It started happening when I started using grep-find mode more intensely, to search through hundreds or even thousands of files. I then started noticing dired do the same thing but not to the same extent because I wasn't working with super-long lists of results.

I'm a heavy org-mode user so I often need to find something in a notes file that's several years old (grepping through old notes files is basically how I do my life. :)

> Also, does this happen in "emacs -Q"?  If not, I'd suspect some
> customization you have on your .emacs init file.

Yes.

(NOTE: See below, Drew's idea worked. Thanks for your help)

Re: Odd slowness in grep and dired modes

[Eli Zaretskii]

> Date: Fri, 21 Mar 2014 09:41:33 -0700 (PDT)
> From: Smith_RS <rsmithpv@gmail.com>
> 
> (NOTE: See below, Drew's idea worked. Thanks for your help)

So let me know if you still want to pursue the original issue.

Re: Odd slowness in grep and dired modes

[Smith_RS]

On Friday, March 21, 2014 9:54:14 AM UTC-7, Eli Zaretskii wrote:
> So let me know if you still want to pursue the original issue.

I'm good, thanks. Like I said, Procmon didn't reveal anything unusual, so the next step would probably be IDE-level debugging, and I'm not set up for that.

Again, thanks.

Re: Odd slowness in grep and dired modes

[Smith_RS]

On Friday, March 21, 2014 7:39:09 AM UTC-7, Drew Adams wrote:
> Do yourself a favor and customize `mouse-1-click-follows-link' to nil.

Thanks, this worked:

(setq mouse-1-click-follows-link nil)

The 450ms delay loop is causing some sort of problem, not sure what that might be or how to debug it.

I am running the pre-built NT Emacs on Windows 7 (SP1 Enterprise) 64-bit. My system has an NVidia 4200M chipset with a GPU, but I don't see that coming into play here.

Thanks again for the help.