| Summary: | kio_http_cache_cleaner is busy waiting | ||
|---|---|---|---|
| Product: | [Frameworks and Libraries] frameworks-kio | Reporter: | Harald Sitter <sitter> |
| Component: | HTTP | Assignee: | KIO Bugs <kio-bugs-null> |
| Status: | REPORTED --- | ||
| Severity: | normal | CC: | kdelibs-bugs-null, nate, oliverst |
| Priority: | NOR | ||
| Version First Reported In: | git master | ||
| Target Milestone: | --- | ||
| Platform: | Other | ||
| OS: | Linux | ||
| Latest Commit: | Version Fixed/Implemented In: | ||
| Sentry Crash Report: | |||
I see something similar with 5.102 on Manjaro Linux with Plasma Mobile. When the system is idle and no applications are open kio_http_cache_cleaner is constantly in the top 3 in powertop with an Usage of about 0,9 ms/s and Events/s of 9,8. Terminating the process with SIGTERM doesn't show much of an improvement overall in consumption and CPU load but it still seems quite unnecessary. |
SUMMARY (this is very poorly researched, but if I don't write it down I'll forget tomorrow) kio_http_cache_cleaner has a loop that is basically always true and inside it waits for 100ms and then either talks to sockets (on the other end I guess is the http.so) or not. it wraps around and the dance continues. This effectively is causing entirely pointless CPU load. Not that big a deal on desktops but in the >0.5% range on plasma mobile. Always. Even when idle. My poor battery :( STEPS TO REPRODUCE 1. run the cleaner OBSERVED RESULT watch it doing stuff when there is nothing to do (at least I think there isn't) EXPECTED RESULT be completely idle unless there's work to be done ADDITIONAL INFORMATION This actually was made worse in a change a while ago that reduced the sleep time from 1s to 100ms because the cleaner wasn't shutting down properly. That did make me wonder why it is busy looping at all though. The application can simply run an eventloop and attach to QLocalServer::newConnection (which I presume will not busy wait) thereby being able to exit somewhat immediately and having zero need for any amount of while(true){} looping.