11 Mar
2016
11 Mar
'16
2:24 p.m.
On Fri, March 11, 2016 11:59 pm, Paul Davis wrote:
On Fri, Mar 11, 2016 at 7:17 AM, Patrick Shirkey
<pshirkey(a)boosthardware.com
Are we absolutely sure this is the case? That Jonathan has not found a
"bug" in JACK2 or the DSP load algorithm?
wrote:
On Fri, March 11, 2016 6:58 pm, Robin Gareus wrote:
JACK
Not quite what I said, but close enough.
20 context switches minimum per process() cycle. This isn't dramatic, but
it is notable. Some of them might not be context switches if the "Mixer"
stuff is actually an example of a multi-client process - I don't know.
On 03/11/2016 08:03 AM, Patrick Shirkey wrote:
> If this cannot be fixed in JACK directly we should be able to spin up
> multiple instances on the same machine and have them play nice with
each
other.
and how would that be different from splitting the current graph in and not preform worse?
Currently it seems that we cant do either so which method is preferable?
According to Jonathan's results he is finding a bottle neck with JACK
DSP
with a single server. In the absense of a fix for JACK so that it is not
a
bottle neck his solution is to run multiple servers on the same machine.
However it seems that it is not possible to have more than 2 instances
of
JACK running on the same machine without using a virtual
machine/environment.
According to Paul the issue is that we should not rely on JACK to create
a
processing graph like Jonathans.
I don't see much difference between a single server with multiple graphs
or multiple servers
That isn't the choice. The choice is threeway:
- reduce overhead caused by context switching between programs
- reduce DSP load by running more in parallel (this is dependent on the
graph; JACK2 will do
the best possible already, so if Jonathan is already using JACK2,
maximum parallelism
is already in use) - reduce the amount of work done by each client.
According to Jonathan his multiple cores are barely reaching 5% usage. How
can JACK_DSP be so high when there is so much room left to play with if
JACK2 is handling the parallelism correctly?
It seems similar to my car telling me that I am red lighting when I am
only going 20km/hr in second.
--
Patrick Shirkey
Boost Hardware Ltd