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Midnight Commander is very slow when starting and changing directories
- From: Krzysztof Bociurko <chanibal at chanibal dot pl>
- To: cygwin at cygwin dot com
- Date: Fri, 8 Jul 2016 16:13:53 +0200
- Subject: Midnight Commander is very slow when starting and changing directories
- Authentication-results: sourceware.org; auth=none
I'm using midnight commander with Cygwin 64 bit on Windows 10 64 bit.
After moving to a new machine and a clean reinstall of windows and
cygwin, my midnight commander started to get very laggy - starting mc,
any change of directory or exiting from finding files (to refresh list
of files in the two panes) takes long seconds. Restarting doesn't
help.
I have no idea what could be the reason for these hiccups. MC normally
works fine: arrow presses work well, viewing and editing is instant,
but this one thing takes up to 10 seconds - changing directories.
Searching in files has a similar lag, but only once (ie not in every
`chdir` it could have done). In non-mc cygwin usage this issue doesn't
happen.
The task manager doesn't show any abnormally high CPU or memory usage
on any process. I have `cygserver` running, using `bash` as my shell
and have no fancy `PS1` settings, my `$CYGWIN` is only
`winsymlinks:native`.
My environment:
* Windows 10 pro 64 bit, up to date
* Not connected to a domain, no network drives
* No anti virus software apart from the one built in Windows
* Two hard drives (system on SSD (C:), D: is a SSHD), quite a few
directory junctions from C: to C:, no loops
* I'm usually using fatty as the terminal, but mintty has the same issues
* GNU Midnight Commander 4.8.17
* cygserver is installed
Here is a strace log, maybe someone has an idea what did go wrong?
http://pastebin.pl/view/9b839815
(recorded with `LOCALE=C strace -q -o /tmp/mc-log mc /tmp`)
In the recorded session I have:
* started mc in `/tmp` directory
* entered `/tmp/NVIDIA Corporation` directory
* went back up (`..`)
* entered `/tmp/mc-chanibal` directory
* went back up (`..`)
* exited with F10
You can see that normalize_posix_path takes a lot of time, but trying
to force the same call with cygpath fails to take so long (more
later).
Additional timing information:
A find of all directories in my `$HOME` takes 4.6 seconds:
$ time find ~ -type d | wc -l
(snipped two directories without permissions)
19919
real 0m4.626s
user 0m0.796s
sys 0m3.765s
A `ls -al` on all of these 19919 directories took a lot of time, but
the average was fairly low:
time (find ~ -type d | while read f; do { time ls -al $f; } \
|& awk '$1 == "real" { printf $2 }' \
| awk -Fm '{printf( "%2.4f", $1 * 60 + $2 )}'; \
echo -e "\t$f"; done \
) >/tmp/ls-time-log ;
(snipped two dirs without permissions)
real 12m21.870s
user 7m4.576s
sys 16m34.446s
The average time to do an `ls -al` is 0.020s, min is 0.017, max is 0.154:
$ awk 'BEGIN { sum=0; min=9999; max=0; minf=""; maxf=""; } \
$1 { sum += $1; \
if(min > $1) { min = $1; minf = $2; }; \
if(max < $1) { max = $1; maxf = $2; } } \
END { print "avg: " sum/NR; print "min: " min " " \
minf; print "max: " max " " maxf }' </tmp/ls-time-log
avg: 0.0204292
min: 0.0170 /cygdrive/c/Users/chanibal/AppData/Roaming/OculusClient/Local
max: 0.1540
/cygdrive/c/Users/chanibal/AppData/Local/Android/sdk/platforms/android-23/data/res/drawable-hdpi
With the overhead of measuring time it averages 16m34s/19919 = 0.499s
per call to `ls -al`, two `awk`s and a iteration of `find`. Not very
good, but not four seconds.
Normalizing with `cygpath` doesn't take long:
$ time strace cygpath -aw /tmp/NVIDIA\ Corporation/ | grep
normalize_posix_path
116 11175 [main] cygpath 3524 normalize_posix_path: src
/tmp/NVIDIA Corporation/
20 11195 [main] cygpath 3524 normalize_posix_path:
/tmp/NVIDIA Corporation/ = normalize_posix_path (/tmp/NVIDIA
Corporation/)
real 0m0.034s
user 0m0.015s
sys 0m0.000s
I have also posted this issue to Super User, but after some discussion
with user Matzeri, he suggested for me to go on this list with this
problem. SU link:
http://superuser.com/questions/1097601/midnight-commander-sometimes-very-slow
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