shibd Memory Usage

[Cantor, Scott]

On 9/26/14, 12:07 PM, "Andy Bennett" <andyjpb at knodium.com> wrote:
>
>> That said, you can certainly check and make sure you're not running
>>Apache
>> prefork to rule that out as a source of RAM spikes.
>
>We're not running Apache at all.
>
>We use the FastCGI binaries but all the memory usage is by shibd.

That isn't my point; there is no thread pool maximum in shibd, so if you
spike it with dozens of requests, it will spin up dozens of threads, each
with a one meg stack. That gets to be a problem if dozens turns into
hundreds. Whether that applies to FastCGI I couldn't say, probably depends
on the web server. Under even high load by a threaded web server, the
number of actual simultaneous requests to shibd won't exceed a couple
dozen and it's not noticeable.

>Yes: we see it eat into swap but it doesn't degrade performance. That
>would correlate with unused pages being swapped out and never touched
>again.

Sounds like it. The stack spikes become a problem because it essentially
exhausts and crashes, so if that's not the case, it's probaby not spiking.

-- Scott