perfSONAR User Q&A and Other Discussion

[Johann Hugo <>]

No, that did not solve it. The problem is still there.  CPU utilization for memcached goes up and just stays there.

 PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAND
  67641 995       20   0   16.3g  12208   2792 S 400.0   0.0 233:11.58 memcached

On Wed, Aug 24, 2022 at 4:37 PM Johann Hugo <> wrote:

Hi

Looks like the CPU utilization for memcached goes up and just stays there (400%). If I down/up memcached, then the CPU utilization goes down to about 6%

Host: Ubuntu 20.04.4 LTS

Docker image: perfsonar/testpoint:latest. (Started with docker-compose)

memcached: VERSION 1.4.15

Top

%Cpu(s):  0.1 us,  6.2 sy,  0.0 ni, 93.4 id,  0.0 wa,  0.0 hi,  0.3 si,  0.0 st
MiB Mem : 128743.4 total, 117899.7 free,   8877.0 used,   1966.7 buff/cache
MiB Swap:   8192.0 total,   8192.0 free,      0.0 used. 118600.7 avail Mem

PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAND
 3292 995       20   0  363996  24208   2832 S 400.3   0.0   2736:33 memcached

I can trigger it by running some iperf2 tests manually.

Adding this option to memcached seems to fix it.

vi /etc/sysconfig/memcached

  OPTIONS="-o hashpower=31"

I think it's related to this issue:

https://github.com/memcached/memcached/issues/855

Regards

Johann

--

SANReN Engineer

South African National Research Network (SANReN)

National Integrated Cyber Infrastructure System (NICIS)

CSIR NextGen Enterprises and Institutions Cluster

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