[asterisk-users] Dahdi_dummy is more accurate than core timer?

[Johan Wilfer]

Hi,

I have some servers that are dedicated to do meetme conferencing. From 
some previous test i concluded that I need to use dahdi_dummy as it is 
more accurate.

If I did use the core timers in dahdi (not loading dahdi_dummy) I got 
bad quality in the conferences and dahdi_test showed 99.6% as worst.

I thought maybe the issue as bad hardware for the timing or something 
else. But today I re-ran these tests on another server showing the same 
thing.

- Can anybody comment on why DAHDI with core timers drop down to 99.6% 
occasionally?
- Is a hardware-card for timing the most efficient way to get timing 
even if I just use the card for the timing?

Below is some stats (trimmed, but you get the idea).

Thanks!

/Johan


** With Dahdi 2.7.0.1, and core timers:

99.998% 99.611% 99.615% 99.997% 99.993% 99.997% 99.996% 99.608%
99.999% 99.612% 99.607% 99.613% 99.999% 99.998% 99.994% 99.609%

--- Results after 177 passes ---
Best: 100.000% -- Worst: 99.604% -- Average: 99.901099%
Cummulative Accuracy (not per pass): 99.998


** With Dahdi 2.7.0.1, and dahdi_dummy loaded:

99.993% 99.998% 99.998% 99.993% 99.996% 99.998% 99.996% 99.998%
99.998% 99.997% 99.999% 99.998% 99.996% 99.998% 99.999% 99.997%

--- Results after 177 passes ---
Best: 100.000% -- Worst: 99.993% -- Average: 99.997738%
Cummulative Accuracy (not per pass): 99.998


** With Dahdi 2.7.0.1, and Wildcard TE220 providing timing

99.981% 99.983% 99.983% 99.982% 99.983% 99.982% 99.984% 99.981%
99.982% 99.983% 99.984% 99.981% 99.980% 99.984% 99.983% 99.983%

--- Results after 177 passes ---
Best: 99.996% -- Worst: 99.974% -- Average: 99.982104%
Cummulative Accuracy (not per pass): 99.982

Kernel: 2.6.32-5-openvz-amd64