High load when cups.path is enabled
Issue
- With
cups.pathstarted, the "%system" CPU utilization is unacceptably high when many print jobs are submitted. - We are seeing a performance issue with our primary point-of-sale Application. The only process with a high load is
systemd. The performance issue causes users to be unable to print. Print jobs are hanging and the server needs to be restarted. - The server runs fine for 2 weeks. Then CUPS starts giving problems, the server then needs to be rebooted. Linux services becomes so slow to a state they then hang. The first noticeable service is CUPS. The print becomes so slow to print.
- We are experiencing gradual increase of system utilization. The systems is acting as CUPS server. After 4 weeks the load on the average load on the system is above 10 and system become unresponsive.
cupsdis utlilising +80-90% of one CPU. It is significantly slowing people from printing. Looking at the TOP command. The %CPU utilisation is 70% to CUPSD/SYSTEMD and each time one increase the other process follows.- When the
cups.pathunit file is started, there is a performance impact that steadily grows over time. We noticed than when we runperf top, the_raw_spin_lockand__fsnotify_update_child_dentry_flagsfunction calls to the kernel hitting about 50%, but that's just on starting it. Those function calls grow over time and negatively impact the entire system. Whencups.pathis restarted, the performance returns to normal but gradually worsens over time.
Environment
- Red Hat Enterprise Linux (RHEL) 7
- Common Unix Printing System (CUPS) 1.6.3
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