Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

arc_summary.py probably displays false data for "Evict Skips" in ARC Misc #6882

Closed
scotws opened this issue Nov 18, 2017 · 0 comments

Comments

Projects
None yet
1 participant
@scotws
Copy link
Contributor

commented Nov 18, 2017

System information

Type Version/Name
Distribution Name Ubuntu
Distribution Version Ubuntu 16.04 LTS
Linux Kernel 4.10.0-38-generic
Architecture x86_64
ZFS Version 0.6.5.9-2
SPL Version 0.6.5.9-1

Describe the problem you're observing

The source code for arc_summary.py contains these lines (line numbers ex vim):

186     output["arc_misc"]['mutex_miss'] = fHits(mutex_miss)
187     output["arc_misc"]['evict_skips'] = fHits(mutex_miss)

Note that both "mutex_miss" and "evict_skips" are both assigned the human-readable number of mutex_miss. Actually, kstats has a parameter "evict_skip" in arcstats that on this system returns the value 10, while the number of mutex misses is given as 0. The parameter "evict_skip", however, is currently not collected at all by arc_summary.py.

It is assumed that the displayed value for evict_skips is wrong and is actually a repeat of the mutex value. Somebody who knows what is actually going on under the hood here needs to confirm that this is in fact a bug and not an intentional assignment for some strange reason.

Describe how to reproduce the problem

Diagnosis is by source code examination and comparison of the arc_summary.py value for "Evict Skips" and the raw value from kstat.zfs.misc.arcstats.evict_skip

scotws added a commit to scotws/zfs that referenced this issue Nov 18, 2017

Fix data on evict_skips in arc_summary.py (zfsonlinux#6882)
Display correct data from kstat arcstats for evict_skips,
which is currently repeating the data from mutex_misses.
Fixes zfsonlinux#6882

Signed-off-by: Scot W. Stevenson <scot.stevenson@gmail.com>

@scotws scotws referenced this issue Nov 18, 2017

Merged

Fix data on evict_skips in arc_summary.py (#6882) #6883

4 of 13 tasks complete

behlendorf added a commit that referenced this issue Nov 18, 2017

Fix data on evict_skips in arc_summary.py
Display correct data from kstat arcstats for evict_skips,
which is currently repeating the data from mutex_misses.
Fixes #6882

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Signed-off-by: Scot W. Stevenson <scot.stevenson@gmail.com>
Closes #6882 
Closes #6883

tonyhutter added a commit to tonyhutter/zfs that referenced this issue Jan 16, 2018

Fix data on evict_skips in arc_summary.py
Display correct data from kstat arcstats for evict_skips,
which is currently repeating the data from mutex_misses.
Fixes zfsonlinux#6882

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Signed-off-by: Scot W. Stevenson <scot.stevenson@gmail.com>
Closes zfsonlinux#6882 
Closes zfsonlinux#6883

tonyhutter added a commit to tonyhutter/zfs that referenced this issue Jan 18, 2018

Fix data on evict_skips in arc_summary.py
Display correct data from kstat arcstats for evict_skips,
which is currently repeating the data from mutex_misses.
Fixes zfsonlinux#6882

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Signed-off-by: Scot W. Stevenson <scot.stevenson@gmail.com>
Closes zfsonlinux#6882 
Closes zfsonlinux#6883

tonyhutter added a commit to tonyhutter/zfs that referenced this issue Jan 18, 2018

Fix data on evict_skips in arc_summary.py
Display correct data from kstat arcstats for evict_skips,
which is currently repeating the data from mutex_misses.
Fixes zfsonlinux#6882

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Signed-off-by: Scot W. Stevenson <scot.stevenson@gmail.com>
Closes zfsonlinux#6882 
Closes zfsonlinux#6883

tonyhutter added a commit to tonyhutter/zfs that referenced this issue Jan 19, 2018

Fix data on evict_skips in arc_summary.py
Display correct data from kstat arcstats for evict_skips,
which is currently repeating the data from mutex_misses.
Fixes zfsonlinux#6882

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Signed-off-by: Scot W. Stevenson <scot.stevenson@gmail.com>
Closes zfsonlinux#6882 
Closes zfsonlinux#6883

Nasf-Fan added a commit to Nasf-Fan/zfs that referenced this issue Jan 29, 2018

Fix data on evict_skips in arc_summary.py
Display correct data from kstat arcstats for evict_skips,
which is currently repeating the data from mutex_misses.
Fixes zfsonlinux#6882

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Signed-off-by: Scot W. Stevenson <scot.stevenson@gmail.com>
Closes zfsonlinux#6882
Closes zfsonlinux#6883

tonyhutter added a commit that referenced this issue Feb 6, 2018

Fix data on evict_skips in arc_summary.py
Display correct data from kstat arcstats for evict_skips,
which is currently repeating the data from mutex_misses.
Fixes #6882

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Signed-off-by: Scot W. Stevenson <scot.stevenson@gmail.com>
Closes #6882 
Closes #6883

Nasf-Fan added a commit to Nasf-Fan/zfs that referenced this issue Feb 13, 2018

Fix data on evict_skips in arc_summary.py
Display correct data from kstat arcstats for evict_skips,
which is currently repeating the data from mutex_misses.
Fixes zfsonlinux#6882

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Signed-off-by: Scot W. Stevenson <scot.stevenson@gmail.com>
Closes zfsonlinux#6882
Closes zfsonlinux#6883
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
You can’t perform that action at this time.