[Freeswitch-users] Call quality assurance

[Stanislav Sinyagin]

it's standard latest Debian 7 on a 8-core Xeon.

Did you explicitly use HPET clock before?



On Fri, Jun 5, 2015 at 12:36 AM, Michael Jerris <mike at jerris.com> wrote:
> To be completely honest on non vm setups I haven't seen anyone with problems
> like this on reasonably recent kernels.  Are you using a distro with an
> older kernel?
>
>
> On Thursday, June 4, 2015, Stanislav Sinyagin <ssinyagin at gmail.com> wrote:
>>
>> Michael, as far as I understand it, it works as follows:
>>
>> timerfd is a kernel's means of providing the system clock to the
>> userland process (freeswitch daemon in our case).
>>
>> The kernel takes the clock from one of available sources, and these
>> sources are either physical or software clocks:
>>
>> # cat /sys/devices/system/clocksource/clocksource0/available_clocksource
>> tsc hpet acpi_pm
>> # cat /sys/devices/system/clocksource/clocksource0/current_clocksource
>> tsc
>>
>> So, TSC was giving stable results, while HPET, although expected to be
>> more precise, was generating errors while the CPU was busy with other
>> jobs.
>>
>>
>>
>>
>>
>>
>> On Thu, Jun 4, 2015 at 9:05 PM, Michael Jerris <mike at jerris.com> wrote:
>> > timerfd would be the preferred timing source on any remotely modern
>> > linux kernel
>> >
>> >> On Jun 4, 2015, at 6:47 AM, Stanislav Sinyagin <ssinyagin at gmail.com>
>> >> wrote:
>> >>
>> >> I summarized some experience gained in a customer project, hopefully
>> >> it will be useful:
>> >>
>> >> https://txlab.wordpress.com/2015/06/02/quality-assurance-for-voip-calls-2/
>> >>
>> >> @Anthony, you suggested to use HPET timer for better precision, but it
>> >> appears that it is affected by the CPU load: while the debian package
>> >> build script was running, the quality of recorded calls has degraded
>> >> -- even that the recording was done onto a TMPFS partition. With the
>> >> default TSC timer, this was not the case.
>> >>
>> >
>> >
>> >
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>
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