Message-ID: <4F35C1E0.2020308@cs.utoronto.ca>
Date: Fri, 10 Feb 2012 20:18:24 -0500
From: Ryan Johnson <ryan DOT johnson AT cs DOT utoronto DOT ca>
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To: "cygwin AT cygwin DOT com" <cygwin AT cygwin DOT com>
Subject: File operations really slow in emacs
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Hi all,

For some reason file operations have become very slow inside emacs 
starting yesterday. It's especially painful when saving a file that's 
managed by mercurial (more than 20 seconds!), but I've seen it on the 
command line as well (x-server takes a similar amount of time to start, 
for example). I'm running the latest everything and I've run rebaseall. 
I verified that Windows Defender did not silently re-enable itself since 
I last disabled it (you can't actually uninstall it) and no other BLODA 
are present on my machine. The problem persists across reboots.

I have vague memories that this has turned up in the past (maybe 12-15 
months ago?) but Google isn't turning up anything. Attaching strace to 
emacs during the save makes it take a full 35 seconds and reports the 
following:

$ cat emacs.strace | awk '{if ($1 > 1000000) { print }}' | grep -v 
timer_thread
26910790 26912157 [main] emacs-X11 5188 child_copy: dll bss - hp 0x264 
low 0x611FC000, high 0x61230770, res 1
1128419 2125655 [main] python2.6 5188 read: read(5, 0x8009DB60, 65536) 
blocking
25850184 32830582 [main] python2.6 5188 stat_worker: 0 = 
(\??\C:\cygwin\cygdrive,0x28BB68)
2672291 36527941 [main] python2.6 5188 fhandler_disk_file::readdir: 0 = 
readdir(0x800C84F0, 0x284BDC) (L"bookmarks.pyc" > "bookmarks.pyc") (attr 
0x20 > type 8)
1076207 64638764 [main] emacs 6568 
fhandler_base_overlapped::wait_overlapped: wfres 0, wores 1, bytes 16

There's some seriously long latencies going on there... 27s for 
child_copy, 26s for stat_worker, and 2.7s for readdir? FYI, that call to 
read() that blocks for 1.1s is accessing a .pyc module in /usr/share, 
not related to the file I actually tried to save.

Relevant package versions, courtesy of cygcheck:
cygwin                      1.7.10-1             OK
emacs                       23.4-1               OK
emacs-X11                   23.4-1               OK
mercurial                   1.9.3-1              OK
python                      2.6.7-1              OK

Any ideas what I might try next?

Thanks,
Ryan


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