Bug 1437018

Summary: lsof -nP is unusable on Fedora when a multi threaded process has many files open
Product: [Fedora] Fedora Reporter: Marcus Sundberg <devel>
Component: lsofAssignee: Jan Rybar <jrybar>
Status: CLOSED EOL QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: 26CC: devel, jrybar, pschiffe, qe-baseos-apps
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Hardware: All   
OS: Linux   
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Clone Of: 1437014 Environment:
Last Closed: 2018-05-29 11:59:49 UTC Type: Bug
Regression: --- Mount Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description Flags
Patch to only list threads/tasks if the -K flag is given. none

Description Marcus Sundberg 2017-03-29 09:50:04 UTC 
+++ This bug was initially created as a clone of Bug #1437014 +++

Description of problem:
When there is at least one process in the system running that has many
open file descriptors and many threads lsof -nP takes a a lot of time
to run and produces huge output.

Version-Release number of selected component (if applicable):
lsof-4.89-5.fc26

How reproducible: Always

Steps to Reproduce:
1. lsof -nP

Actual results:
Takes a long time to traverse all threads of all processes.

Expected results:
Only traverse processes, unless -K flag is given.

--- Additional comment from Marcus Sundberg on 2017-03-29 05:41 EDT ---



--- Additional comment from Marcus Sundberg on 2017-03-29 05:44 EDT ---



--- Additional comment from Marcus Sundberg on 2017-03-29 05:46:15 EDT ---

Example running standard and patched lsof in an EL7 desktop session:

Standard EL7 lsof:
$) time lsof -nP | wc -c
14117646

real	0m1.430s
user	0m0.648s
sys	0m0.789s
$) ./fd-and-threads &
[1] 30452
$) time lsof -nP | wc -c
75110357

real	0m13.096s
user	0m4.128s
sys	0m8.968s
$) 

Patched lsof:
$) time lsof -nP | wc -c
1748246

real	0m0.214s
user	0m0.087s
sys	0m0.131s
$) ./fd-and-threads &
[1] 31585
$) time lsof -nP | wc -c
1822372

real	0m0.247s
user	0m0.087s
sys	0m0.162s
$) time lsof -nPK | wc -c
68403949

real	0m12.946s
user	0m4.125s
sys	0m8.828s
$)
Comment 1 Marcus Sundberg 2017-03-29 09:52:21 UTC 
See attachment 1267267 [details] for the fd-and-threads sample program.
Comment 2 Marcus Sundberg 2017-03-29 09:53:25 UTC 
The issue is the same in Fedora 24, Fedora 25 and rawhide. Feel free to
clone as desired.
Comment 3 Marcus Sundberg 2017-03-29 09:55:15 UTC 
Created attachment 1267269 [details]
Patch to only list threads/tasks if the -K flag is given.
Comment 4 Peter Schiffer 2017-03-30 07:36:21 UTC 
Marcus, thanks for the bug and the patch! Can I ask - did you contacted upstream about this problem? If not, could you? Try to send him an explanation with sample program and the patch. If he accepts it (or modified version), please, let me know.

Thanks,

peter
Comment 5 Peter Schiffer 2017-03-30 07:36:58 UTC 
Forgot to mention, here's his home page with email address: https://people.freebsd.org/~abe/
Comment 6 Peter Schiffer 2017-05-19 15:12:03 UTC 
Marcus, were you able to talk to the upstream?
Comment 7 Marcus Sundberg 2017-05-31 13:24:09 UTC 
There is apparently a pre-release of lsof 4.90 which has a new -Ki
option that disables listing threads:

ftp://lsof.itap.purdue.edu/pub/tools/unix/lsof/NEW/lsof_4.90C.linux.tar.bz2

I tried to argue that omitting threads should be the default, but he
disagreed with the motivation that lsof has always listed "everything"
by default.

Would you prefer a patch backporting the -Ki option instead of my current
patch?
Comment 8 Peter Schiffer 2017-05-31 14:01:11 UTC 
Hi Marcus,

thanks for the update. If you could provide a patch backporting the -Ki option from upstream, I'll update rawhide and f26 builds. (Please don't forget to update the man page as well.)

Thank you.

peter
Comment 9 Peter Schiffer 2018-02-21 15:47:42 UTC 
New version of lsof including the patch from upstream is now available in rawhide: https://koji.fedoraproject.org/koji/buildinfo?buildID=1048147
Comment 10 Fedora End Of Life 2018-05-03 08:38:35 UTC 
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Comment 11 Fedora End Of Life 2018-05-29 11:59:49 UTC 
Fedora 26 changed to end-of-life (EOL) status on 2018-05-29. Fedora 26
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