Developers of Sympa

[IKEDA Soji <address@concealed>]

Hi developers,

I forgot to report for long time about a load test.

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Sympa load test
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Description: https://git.io/fxCUl
Result: https://git.io/fxCfj (PDF, Japanese in legends)

p.2:

With Sympa by default setting, inject 10 messages/sec sized 1 MiB
constantly.

X-axis is ellapsed time, and Y-axis is delay of delivery,
e.g. a message injected at 20 sec after beginning of test takes
approximately 36 seconds before it is passed to sendmail.

Delay increases more and more.  It means that Sympa cannot catch up
messages injected one after another.

p.3:

Increase incoming_max_count (number of sympa_msg.pl worker) and
bulk_max_count (number of bulk.pl children) to 4 and 16 respectively.

In the first 15 seconds, new bulk.pl children are spawned and
make stuation stable. However afterward Sympa still couldn't catch
up.

p.4:

With trial-and-error, workers/children are increased to 8 and 16,
and stuation become stable.

p.5:

Distribution of delays with setting above.  X-axis is rank of delay
(sec), and Y-axis is number of messages.  Mode is approx. 3 secs.

pp.6-12:

Same trials with messages sized 100 kiB.

At last, we increased injection rate up to 40 messages/sec and
aborted tests (as we must hand the machine back).

Comment
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Even if delivery system of Sympa was intended to be efficient and
robust, it might be broken by higher traffic.

Furthermore, even if the software looks working as expected with
low performance machine, higher-performance environment might
break software logic (e.g. race condition on file lock).

So we tried to verify.

The result was pleasing: Sympa was proven to handle relatively high
trafic.

However, the result is not suffice: It is not obvious how Sympa behave
with more higher trafic, e.g. larger messages, beyond 10^2 / sec
injection.

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Regards,
-- Soji

-- 
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