/proc/pid/stat cpu ticks are not updated
I'll be as precise as possible:
On my RHEL7 machine (3.10.0-514.el7.x86_64), /proc/PID/stat is not updated in respect to CPU ticks, sometimes for a minute and more. I'm clearly at a loss how this can be possible. Here some additional information:
- The process is a very long running one (our database server) with around 9.000.000.000 ticks user time in total and around 800 ticks per second.
- minor page faults are updated correctly. Thats also the only value changing.
- forked subprocesses (workers) are updated correctly.
- The behaviour changes with time. Its almost exactly 80 Minutes between these "stalls", where the gaps are biggest. Then it gradualy normalises after 20 Minutes when values are fine again.
This behaviour completely messes up top, causing it to show values of 0% CPU usage most of the time and suddenly spiking to 1600 (we have 16 Cores there). And that with a database that is only licenced for (and limited to) 8 cores.
Furthermore, it confuses our monitoring tool, which seems to use the same values. When on a 1-minute average, what we get is the image depicted in the screenshot.
Obviously, the database does not really stall during this time. The question is, has anyone seen such a behaviour before? Unfortunately, I cannot simply restart the process, wich i would do if it were anything other than our main database :)
linux-kernel proc top
asked Sep 25 '18 at 13:00
Christian PlatzerChristian Platzer
12
add a comment |
I'll be as precise as possible:
On my RHEL7 machine (3.10.0-514.el7.x86_64), /proc/PID/stat is not updated in respect to CPU ticks, sometimes for a minute and more. I'm clearly at a loss how this can be possible. Here some additional information:
- The process is a very long running one (our database server) with around 9.000.000.000 ticks user time in total and around 800 ticks per second.
- minor page faults are updated correctly. Thats also the only value changing.
- forked subprocesses (workers) are updated correctly.
- The behaviour changes with time. Its almost exactly 80 Minutes between these "stalls", where the gaps are biggest. Then it gradualy normalises after 20 Minutes when values are fine again.
This behaviour completely messes up top, causing it to show values of 0% CPU usage most of the time and suddenly spiking to 1600 (we have 16 Cores there). And that with a database that is only licenced for (and limited to) 8 cores.
Furthermore, it confuses our monitoring tool, which seems to use the same values. When on a 1-minute average, what we get is the image depicted in the screenshot.
Obviously, the database does not really stall during this time. The question is, has anyone seen such a behaviour before? Unfortunately, I cannot simply restart the process, wich i would do if it were anything other than our main database :)
linux-kernel proc top
asked Sep 25 '18 at 13:00
Christian PlatzerChristian Platzer
12
add a comment |
I'll be as precise as possible:
On my RHEL7 machine (3.10.0-514.el7.x86_64), /proc/PID/stat is not updated in respect to CPU ticks, sometimes for a minute and more. I'm clearly at a loss how this can be possible. Here some additional information:
- The process is a very long running one (our database server) with around 9.000.000.000 ticks user time in total and around 800 ticks per second.
- minor page faults are updated correctly. Thats also the only value changing.
- forked subprocesses (workers) are updated correctly.
- The behaviour changes with time. Its almost exactly 80 Minutes between these "stalls", where the gaps are biggest. Then it gradualy normalises after 20 Minutes when values are fine again.
This behaviour completely messes up top, causing it to show values of 0% CPU usage most of the time and suddenly spiking to 1600 (we have 16 Cores there). And that with a database that is only licenced for (and limited to) 8 cores.
Furthermore, it confuses our monitoring tool, which seems to use the same values. When on a 1-minute average, what we get is the image depicted in the screenshot.
Obviously, the database does not really stall during this time. The question is, has anyone seen such a behaviour before? Unfortunately, I cannot simply restart the process, wich i would do if it were anything other than our main database :)
linux-kernel proc top
asked Sep 25 '18 at 13:00
Christian PlatzerChristian Platzer
12
I'll be as precise as possible:
On my RHEL7 machine (3.10.0-514.el7.x86_64), /proc/PID/stat is not updated in respect to CPU ticks, sometimes for a minute and more. I'm clearly at a loss how this can be possible. Here some additional information:
- The process is a very long running one (our database server) with around 9.000.000.000 ticks user time in total and around 800 ticks per second.
- minor page faults are updated correctly. Thats also the only value changing.
- forked subprocesses (workers) are updated correctly.
- The behaviour changes with time. Its almost exactly 80 Minutes between these "stalls", where the gaps are biggest. Then it gradualy normalises after 20 Minutes when values are fine again.
This behaviour completely messes up top, causing it to show values of 0% CPU usage most of the time and suddenly spiking to 1600 (we have 16 Cores there). And that with a database that is only licenced for (and limited to) 8 cores.
Furthermore, it confuses our monitoring tool, which seems to use the same values. When on a 1-minute average, what we get is the image depicted in the screenshot.
Obviously, the database does not really stall during this time. The question is, has anyone seen such a behaviour before? Unfortunately, I cannot simply restart the process, wich i would do if it were anything other than our main database :)
linux-kernel proc top
linux-kernel proc top
asked Sep 25 '18 at 13:00
Christian PlatzerChristian Platzer
12
asked Sep 25 '18 at 13:00
Christian PlatzerChristian Platzer
12
edited Sep 25 '18 at 13:07
Christian Platzer
asked Sep 25 '18 at 13:00
Christian PlatzerChristian Platzer
12
asked Sep 25 '18 at 13:00
Christian PlatzerChristian Platzer
12
asked Sep 25 '18 at 13:00
Christian PlatzerChristian Platzer
12
12
add a comment |
add a comment |
1 Answer
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Identitcal issue have been on our system.
Are you still having trouble with this?
Could you explain a little bit more about your environment such as whether the machine is physical or virtual.
If it's VM, what is the host OS?
There are issue and fixed report that related to this in RHEL doc a few years ago.
https://access.redhat.com/solutions/338733
That's why we have a suspicion on host OS.
I really appreciate any information you can share!
answered 16 mins ago
honserhonser
1
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1 Answer
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1 Answer
1
active
oldest
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active
oldest
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active
oldest
votes
Identitcal issue have been on our system.
Are you still having trouble with this?
Could you explain a little bit more about your environment such as whether the machine is physical or virtual.
If it's VM, what is the host OS?
There are issue and fixed report that related to this in RHEL doc a few years ago.
https://access.redhat.com/solutions/338733
That's why we have a suspicion on host OS.
I really appreciate any information you can share!
answered 16 mins ago
honserhonser
1
New contributor
honser is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |
Identitcal issue have been on our system.
Are you still having trouble with this?
Could you explain a little bit more about your environment such as whether the machine is physical or virtual.
If it's VM, what is the host OS?
There are issue and fixed report that related to this in RHEL doc a few years ago.
https://access.redhat.com/solutions/338733
That's why we have a suspicion on host OS.
I really appreciate any information you can share!
answered 16 mins ago
honserhonser
1
New contributor
honser is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |
Identitcal issue have been on our system.
Are you still having trouble with this?
Could you explain a little bit more about your environment such as whether the machine is physical or virtual.
If it's VM, what is the host OS?
There are issue and fixed report that related to this in RHEL doc a few years ago.
https://access.redhat.com/solutions/338733
That's why we have a suspicion on host OS.
I really appreciate any information you can share!
answered 16 mins ago
honserhonser
1
New contributor
honser is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Identitcal issue have been on our system.
Are you still having trouble with this?
Could you explain a little bit more about your environment such as whether the machine is physical or virtual.
If it's VM, what is the host OS?
There are issue and fixed report that related to this in RHEL doc a few years ago.
https://access.redhat.com/solutions/338733
That's why we have a suspicion on host OS.
I really appreciate any information you can share!
answered 16 mins ago
honserhonser
1
New contributor
honser is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
answered 16 mins ago
honserhonser
1
New contributor
honser is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
answered 16 mins ago
honserhonser
1
answered 16 mins ago
honserhonser
1
1
New contributor
honser is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
honser is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
honser is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
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