Re: [Libevent-users] Measuring load

[Nick Mathewson <nickm@xxxxxxxxxxxxx>]

On Sat, Jul 31, 2010 at 8:21 AM, Matthew Wild <mwild1@xxxxxxxxx> wrote:
> Hi all,
>
> I've been wondering if there is some way I can add load measurement to
> my application when using libevent.
>
> How to define "load" is open to interpretation, but generally I refer
> to the case where events are being fired faster than my application is
> processing them. Similar to the loadavg found on most *nix systems, I
> guess this would be based on the average number of outstanding events
> over a certain period of time.
>
> Assuming this is the best approach, I searched for a way to retrieve a
> list of events awaiting processing from libevent, but couldn't find
> anything. Am I missing it, or is there no way to get this information?

There isn't an exposed interface to get the list of pending events
from an event base right now, but it would be interesting to think
about ways to get load information in future versions of Libevent
without hurting performance.

Other measurements you might care about could include:
  * Average delay between getting a result from the dispatch function
and calling it again.
  * Average number of low-priority events starved for attention while
high-priority events are getting processed.
  * Average delay between an event becoming active and its callback finishing.

What else would folks find interesting?

-- 
Nick
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