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https://issues.apache.org/jira/browse/AURORA-1939?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16095732#comment-16095732
]
Reza Motamedi edited comment on AURORA-1939 at 7/21/17 3:42 AM:
----------------------------------------------------------------
Following [~StephanErb]'s suggestion tried to guard the psutil's `oneshot` as a
critical section. It does not seem to work however:
{code}
...
from threading import Lock
...
oneshot_lock = Lock()
def process_to_sample(process):
""" Given a psutil.Process, return a current ProcessSample """
try:
with oneshot_lock:
with process.oneshot():
# the nonblocking get_cpu_percent call is stateful on a particular
Process object, and hence
# >2 consecutive calls are required before it will return a non-zero
value
rate = process.cpu_percent(0.0) / 100.0
cpu_times = process.cpu_times()
...
{code}
was (Author: rezam):
Following [~StephanErb]'s suggestion tried to guard the psutil's `oneshot` as a
critical section. It does not seem to work however:
```
...
from threading import Lock
...
oneshot_lock = Lock()
def process_to_sample(process):
""" Given a psutil.Process, return a current ProcessSample """
try:
with oneshot_lock:
with process.oneshot():
# the nonblocking get_cpu_percent call is stateful on a particular
Process object, and hence
# >2 consecutive calls are required before it will return a non-zero
value
rate = process.cpu_percent(0.0) / 100.0
cpu_times = process.cpu_times()
...
```
> Thermos landing (host) page reports incorrect CPU rates when it is busy
> -----------------------------------------------------------------------
>
> Key: AURORA-1939
> URL: https://issues.apache.org/jira/browse/AURORA-1939
> Project: Aurora
> Issue Type: Bug
> Reporter: Reza Motamedi
> Priority: Minor
>
> Thermos Observer uses `psutil` to monitor resource consumption of Thermos
> Processes. On a busy machine, I have noticed negative CPU values when
> visiting the Thermos landing page.
> In my test I reproduced this by starting many processes that constantly
> create short lived children. This indicates that in time between
> `process_collector_psutil` looks up the Process children and the time it
> calculates the CPU time the pid of the child is actually reused by another
> much younger process, which leads to negative CPU times.
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