Re: [alsa-devel] Re: Bad MIDI performance : 10ms latency instead of the expected 1-1.5ms

Re: [alsa-devel] Re: Bad MIDI performance : 10ms latency instead of the expected 1-1.5ms

[Paul Barton-Davis]

>200bytes/sec is just rudiculous , how do you plan to drive an external synth
>with that little MIDI bandwidth ?

check with creative that they actually intend this as a use of the
card :)

but seriously, Benno you know the difference between a system in which
a single application can take full control of the machine by having a
callback run in interrupt context and one like Linux. with the former
system, the 2 byte FIFO isn't a problem, or rather, it isn't much of a
problem. 

>If this is true, then I will throw away my AWE64 and buy an AudioPCI :-)

Yes, basically all your problems arise from using consumer
hardware. In particular, consumer hardware that isn't designed to work
correctly in (1) a multi-user, multitasking, virtual memory OS and (2)
isn't really intended to do much more than make noise for games and
sound effects.

As I never tire of saying, Hoontech's card is $39 and its hard to beat.

--p

Re: [alsa-devel] Re: Bad MIDI performance : 10ms latency instead of the expected 1-1.5ms

[Benno Senoner]

> 
> >200bytes/sec is just rudiculous , how do you plan to drive an external synth
> >with that little MIDI bandwidth ?
> 
> check with creative that they actually intend this as a use of the
> card :)

> 
> but seriously, Benno you know the difference between a system in which
> a single application can take full control of the machine by having a
> callback run in interrupt context and one like Linux. with the former
> system, the 2 byte FIFO isn't a problem, or rather, it isn't much of a
> problem. 

Yes under DOS this is not a problem since the sequencer it the only app
which runs, but on a multitasking system crappy hardware can monopolize
the CPU quite a bit.

When I get a 2nd PC, I will test the following:
Windoze PC+ AWE64 running a sequencer with the MIDI port in thru mode,
connect the 2nd PC running Linux (with a DECENT MIDI interface)
and then send the full MIDI bandwidth out to the poor windoze box,
and measure the midi delay and especially the CPU usage on the box.
:-)
 

> 
> >If this is true, then I will throw away my AWE64 and buy an AudioPCI :-)
> 
> Yes, basically all your problems arise from using consumer
> hardware. In particular, consumer hardware that isn't designed to work
> correctly in (1) a multi-user, multitasking, virtual memory OS and (2)
> isn't really intended to do much more than make noise for games and
> sound effects.
> 
> As I never tire of saying, Hoontech's card is $39 and its hard to beat.

Do you know if this card is available in Europe ( Italy/Germany) ?
I heard that the S/N ratio is quite good.
(Is this card capable of providing 2 separate stereo outputs
( 4 chans ?)

regards,
Benno.

Re: [alsa-devel] Re: Bad MIDI performance : 10ms latency instead of the expected 1-1.5ms

[Paul Barton-Davis]

>Im the only one that have problems with perfomance while receiving
>midi data ?  It is droping a lot of events. Oss don't drop so mush,
>but alsa is useless. Is it SMP problem ? Low irq responce times ? I
>have a SB PCI 128 and a hoontech and have the same problem with
>both. (The hoontech is only avalible with alsa driver)

I don't know if you're the only one, but certainly not all people with
the hoontech's have this problem, even with SMP systems. I have a
Hoontech 4D-NX and a Tropez+, and my MIDI response and functionality
is as good as any MIDI hardware makes possible. I lose no events, even
in the face of a lot of MIDI data transmission (e.g. a MIDI fader box
being actively manipulated at the same time as a MIDI h/w sequencer
and an external synth that sends active sense bytes every few msecs).

You may have a bigger potential problem right now in terms of quoting
irrelevant messages in their entirety and sending MIME-based mail to
various email lists which have a majority of members who don't like
it.

--p