Looks like writev syscall does happen instantly, and tail on the host that is running the uwsgi process is also returning the newly written data instantly. Tail on a bastion host seems to see seconds of delay for me, whether I use `tail -f` `tail -F` or `watch tail`. However, the delay is gone if I use `tail -f` on the uwsgi host. Looks like the kernel is buffering the data...
YiFei Zhu On Thu, Jun 25, 2020 at 8:12 AM Roy Smith <[email protected]> wrote: > > https://tools.wmflabs.org/spi-tools/spi/ > > To generate a request, click the "Sock Info" button or the "Index" link. > > The log file is /data/project/spi-tools/uwsgi.log > > Thanks. > > > > On Jun 25, 2020, at 2:12 AM, YiFei Zhu <[email protected]> wrote: > > My guess is output stream buffering, at either the libc level or the > python level. > > Which tool is this? I can probably strace and see if that is the case. > > YiFei Zhu > > > On Wed, Jun 24, 2020 at 10:16 PM Roy Smith <[email protected]> wrote: > > > I'm running a web server with "webservice --backend=kubernetes python3.7". > As I tail the uwsgi.log file, requests to my server get logged with very long > delays. I just timed one at about a minute and a half between when the > request was served (03:07:57 UTC 2020) and when it showed up in the log file > (03:09:23 UTC 2020). > > What is going on here? Is there some way to make it not do this? > _______________________________________________ > Wikimedia Cloud Services mailing list > [email protected] (formerly [email protected]) > https://lists.wikimedia.org/mailman/listinfo/cloud > > > _______________________________________________ > Wikimedia Cloud Services mailing list > [email protected] (formerly [email protected]) > https://lists.wikimedia.org/mailman/listinfo/cloud > > > _______________________________________________ > Wikimedia Cloud Services mailing list > [email protected] (formerly [email protected]) > https://lists.wikimedia.org/mailman/listinfo/cloud _______________________________________________ Wikimedia Cloud Services mailing list [email protected] (formerly [email protected]) https://lists.wikimedia.org/mailman/listinfo/cloud
