Agreed. Thanks On Dec 11, 2015 17:41, "Alex Rousskov" <[email protected]> wrote:
> On 12/10/2015 02:23 PM, Kinkie wrote: > > On Thu, Dec 10, 2015 at 10:07 PM, Alex Rousskov wrote: > >> On 12/10/2015 11:25 AM, Francesco Chemolli wrote: > >>> And it is actually pretty detectable: let’s choose an arbitrary size > >>> of the shared segment and output a warning message to cache.log. This > >>> won’t help with the speed, but it might help with the confusion.. > > > >> 2015/12/09 11:24:51| Total mlock() delay exceeded 5.3 seconds. See > >> shared_memory_locking in squid.conf.documented. > > > > I was thinking more of something _before_ the delay: > > e.g. if shared memory is > 100mb, then > > "locking XXX mbytes of shared memory. On some systems this may require > > a long time. Squid is not dead, it's just thinking" > > > I think the post-event warning is better: > > * It is difficult to guess which segment sizes will cause significant > delays in a given environment. > > * Squid allocates many segments and a few large segments. Warning the > admin before each large allocation would create a lot of noise. Not > warning the admin before some large allocations would kind of defeat the > idea of the preemptive warning itself. > > * There is a possibility that the significant (from admin point of view) > startup delay is caused by the _cumulative_ effect of locking various > shared memory segments and not by any single segment. > > * Warning folks about something that has not happened yet and may never > happen increases log noise. In this particular case, we _can_ warn when > we know that startup was significantly delayed because of locking, > reducing that noise. > > * There is a good chance that somebody concerned about startup delays > will notice the first line printed _after_ the delay. > > > Are you sure that preemptive per-segment warnings are better than an > acknowledgement of the problem after it happens? Do you think the latter > is likely to be missed by admins investigating startup delays? > > > > and then when it's done "shared memory locking of X Mb done in Y > > seconds. This may be normal depending on the size of the shared memory > > area". > > I would rather put explanations in squid.conf.documented so that we do > not have to risk misleading folks when discussing complex issues using a > one-line statement. Besides, we need to point folks to options > controlling this behavior (in case they do not think that slow startup > is "normal" for them). > > > Thank you, > > Alex. > >
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