[Asterisk-code-review] formats: Changed file-block reading from 20ms to 10ms. (asterisk[11])

[Corey Farrell]

Corey Farrell has posted comments on this change.

Change subject: formats: Changed file-block reading from 20ms to 10ms.
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Patch Set 1: Code-Review-1

> > What kind of performance impact does this have on the system?
 > 
 > That is a valid question. However, I do not have the resources to
 > test this, at least I do not know how to do this. If that question
 > is targeted at me and not the Asterisk team and/or the whole
 > community in general, then I need guidance how I can help to go
 > further with this commit/review = do this performance test. Until
 > then, I consider this a question targeted at the whole community.
 > 
 > Joshua, in that case and because I am not sure whether code-review
 > comments are send to any mailing list, please, express your concern
 > in the related issue report ASTERISK-25483 as well. That way, the
 > interested community receives a notification via the mailing list.

By operating on 10ms at a time instead of 20ms at a time, loops on audio would run 100 times per second instead of 50.  I have not done testing but logic says this would double the overhead of the loop itself.  I worry about possible cumulative added overhead when using things like Record, MixMonitor, audio hooks, bridging or any other path audio can travel.

For me to consider supporting any change like this I'd want to see that it fixes a bug with real-world consequences.  I do not expect this to be the case.  Cisco references ITU G.114 as stating up to 150ms is acceptable for most user applications [1].  That is for national telecom's, the next paragraph says that for private voice networks 200-250ms is ok.  See also the section on "Packetization Delay" where it mentions balancing CPU load and delay.

[1] http://www.cisco.com/c/en/us/support/docs/voice/voice-quality/5125-delay-details.html#standarfordelaylimits

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Gerrit-MessageType: comment
Gerrit-Change-Id: I5aa21a3c4f3a4ea78ac3cc80a3883317648464a4
Gerrit-PatchSet: 1
Gerrit-Project: asterisk
Gerrit-Branch: 11
Gerrit-Owner: Alexander Traud <pabstraud at compuserve.com>
Gerrit-Reviewer: Alexander Traud <pabstraud at compuserve.com>
Gerrit-Reviewer: Anonymous Coward #1000019
Gerrit-Reviewer: Corey Farrell <git at cfware.com>
Gerrit-Reviewer: Joshua Colp <jcolp at digium.com>
Gerrit-Reviewer: Matt Jordan <mjordan at digium.com>
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