[Freeswitch-users] Choppy sound with PCMU

Mon Dec 7 12:58:55 PST 2009

What do you want me to check while running these tests? Sound quality (it's
good now even with original 1.0.4). Or CPU utilization?

It's Debian 4.

Anthony Minessale-2 wrote:
> 
> Did you do each thing alone too to tell the difference?
> -hp alone, disable monotonic alone (i did not see you mention the disable
> monotonic)
> 
> as for your 4ms thing, yes we require high resolution timing, if we ask to
> sleep 1000 microseconds that is what we need it to sleep for or at least
> as
> close as possible, and the main reason that thread is never sleeping is
> because you can't actually count on it to run every 1ms but you mostly
> can.
> Hence the whole philosophy on only making 1 thread run hot all the time to
> ensure that the rest don't have to repeat the same algorithm.  We focus on
> high end performance this was the point of your experimentation because we
> will need to use a compile time defines and other logic to make it more
> efficient on your platform, a platform which we are not using.  I am
> curious
> what would happen if you install Kristian's astlinux on one of your
> devices,
> i think you should also compare the kernel versions.
> 
> 
> What OS are you running anyway?
> 
> Here are some more things to try (running plain trunk with no mods) do
> these
> systematically each alone and all together with/without -hp or disable
> monotonic etc to see what different combos create
> 
> comment out this line (line 10)
> #define DISABLE_1MS_COND
> 
> rebuild, this tells it to run a conditional at 1ms in the same timer
> thread
> which will make all the switch_cond_next share a 1ms conditional instead
> of
> doing microsleeps
> 
> next
> 
> some kernels/devices work better using select(0) for sleep where others
> work
> better using usleep.
> comment out line 109
> apr_sleep(t);
> 
> and try
> usleep(t)
> 
> also mac works better using nanosleep so you could try changing it so it
> uses the code starting at 101 instead.
> 
> 
> also your claim about JS should be investigated because I do not think it
> should be the case.
> but you may want to move this to a jira http://jira.freeswitch.org
> 
> As for the asterisk comparison,
> not sure how to answer you, that's your decision.
> 
> 
> 
> On Mon, Dec 7, 2009 at 9:28 AM, eaf <erandr-junk at usa.net> wrote:
> 
>>
>> Here is what I found...
>>
>> I tried high-priority scheduling as per your suggestion, reniced the
>> program
>> explicitly, rewrote timer thread to sleep on cond. variable and activate
>> only when there are timers and only when the timer actually had to be
>> clicked, turned off SQL thread and removed polling from sofia profile
>> thread.
>>
>> That pretty much eliminated all idle 1ms sleepers that were there except
>> for
>> three in sofia itself (su_epoll_port). And when I was about to be happy,
>> I
>> found that two outgoing calls through my VOIP providers when bridged
>> together showed terrible distortions. I undid all my changes, tried
>> 1.0.4,
>> trunk (noticed btw that when I bridge two calls via loopback in JS in the
>> trunk I must keep JS running, or the calls get terminated - NOT the same
>> as
>> in 1.0.4 where exitting JS left calls running), got pretty much the same
>> sad
>> results. At the same time calls bridged by freeswitch between LAN and any
>> of
>> the VOIP providers behaved just fine. And calls bridged by Asterisk any
>> way
>> were fine too. So that pretty much looked like the end of the freeswitch
>> trials for me.
>>
>> But then I timed your code, mine and found that all those 1ms sleeps that
>> your timer thread was doing (and all those pollers were doing as well)
>> were
>> actually 4ms sleeps because you know what unless kernel is configured
>> with
>> HZ=1000, you can't sleep for less than 4ms (HZ=250) or perhaps even 10ms
>> (HZ=100). Mine was 250.
>>
>> This actually meant that the original timer thread was firing once,
>> sleeping
>> for 4ms, firing 3 more times back-to-back, sleeping for 4ms more, firing
>> 4
>> times back-to-back, etc. It was still firing 20ms timers on time, but
>> 30ms
>> ones of course were not, since 30ms doesn't divide by 4 evenly. Plus
>> whoever
>> relied on runtime.reference or switch_micro_time_now() were kind of
>> screwed
>> because both were running jumpy. Plus whoever assumed that
>> apr_sleep(1000)
>> or cond_yield() was sleeping for 1ms were also in for a surprise. It felt
>> satisfying to find that, however it didn't explain why the same
>> distortions
>> were observed with rewritten timer thread and disabled RTP timers.
>>
>> Anyway, I sighed (pretty much like you) and recompiled the kernel with
>> HZ=1000. Recompiling kernel on these ALIX boards is fun. If smth goes
>> south,
>> you need to hook up serial console and see what the heck went wrong.
>>
>> That eliminated distortions, ha! But made freeswitch more CPU hungry. Now
>> the remaining 1ms threads sitting in sofia epoll were really polling for
>> 1ms, not 4, and freeswitch was consistently sitting in the first line of
>> the
>> top chart showing 3% CPU utilization when idle.
>>
>> Don't know whether it's because of the remaining epolls in sofia or
>> whether
>> it's because there are still some threads left in freeswitch that I
>> neglected to change because they were sleeping with 100ms interval, so I
>> figured, who cares. Maybe when all things come together (sofia, 100ms*N)
>> freeswitch ends up spending 3% of CPU while doing pretty much nothing.
>>
>> Btw, compared with Asterisk, the latter is not even visible on the first
>> top's screen and spends 1% CPU when bridging two G711 calls and recording
>> them to disk.
>>
>> So, at this time I have both original Asterisk and FS setups running. One
>> is
>> seemless but clumsy in configuration, the other one is neat and stylish
>> but
>> too preoccupied with smth... Should I look into sofia epollers? That's
>> kind
>> of deep in the code. Or should I just stick with Asterisk?
>>
>>
>>
>>
>>
>> Anthony Minessale-2 wrote:
>> >
>> > There is another user here with a 300mhz box.  I am willing to
>> investigate
>> > this improved performance for weak devices but I need to do it in a
>> sane
>> > cross-platform way.
>> >
>> >
>> > On Fri, Dec 4, 2009 at 1:32 PM, Yossi Neiman
>> > <freeswitch at cartissolutions.com
>> >> wrote:
>> >
>> >> A word to the wise to the general FreeSWITCH community:  If Anthony
>> >> Minessale suggests that you try to do any number of things, it's a
>> very
>> >> good idea to try all those ideas before continuing on.  I've known
>> him,
>> >> MikeJ, and bkw for several years, and they almost always have very
>> good
>> >> ideas as to troubleshoot a problem in FreeSWITCH.  It's extremely
>> >> frustrating to try to help people out who won't try the provided
>> >> suggestions first.
>> >>
>> >> And note directly to "eaf" - bogomips is quite possibly the least
>> >> significant bit of data about a cpu that you will get out of
>> >> /proc/cpuinfo...  The name itself - bogo, means bogus.
>> >> http://en.wikipedia.org/wiki/Bogomips
>> >>
>> >> -Yossi
>> >>
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>> >
>> >
>> >
>> > --
>> > Anthony Minessale II
>> >
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> 
> 
> 
> -- 
> Anthony Minessale II
> 
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