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Topic: Strange performance problem (Read 1944 times) |
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chkk
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MIDI-OX rules
 
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Strange performance problem
« on: Aug 28th, 2001, 6:42am » |
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Hi Jamie,
as you might know by my last posts, I have been putting the MIDI-OX COM interface to a hard test in the last days ...
I discovered a very strange - but reproducible - performance problem.
Take a very simple MIDI-OX COM client which simple forwards the event it gets from MIDI-OX to an other output, no processing at all.
When you quickly play a lot of notes on the keyboard (using all 10 fingers helps ...) for some minutes, suddenly the notes will come out with a very heavy delay (more than a second), sounds as if MIDI-OX is close to breaking down ... only way to stop it is to stop playing for some seconds.
Watching the Windows 2000 task manager reveals, that the CPU load for MIDI-OX increases from about 5 percent (when everything is OK) to about 40 percent (when the notes get delayed). There is a basic workload of about 45 percent from Cubase with some VST instruments, this workload does not change.
If I log the time required for the processing in the event handler for the MIDI-OX Com object, there is no increase at the moment the problems start, processing time is 0-2 ms.
There is no paging (576MB, about 400 free ...), I disabled the input/output display in MIDI-OX to save some CPU cycles.
Any ideas ?
Greetings,
Christian
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| « Last Edit: Aug 28th, 2001, 6:46am by chkk » |
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Jamie OConnell
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Re: Strange performance problem
« Reply #1 on: Aug 28th, 2001, 7:54am » |
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Are you using MIDI Yoke NT when this happens? There is a known occasional latency problem with the NT version of MIDI Yoke because of it's implementation. I have never seen any latency problem using only MIDI-OX.
The task manager will attribute the problem to one application or another because MIDI Yoke NT creates worker threads on behalf of attached applications.
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--Jamie
Music is its own reward.
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chkk
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Re: Strange performance problem
« Reply #2 on: Aug 28th, 2001, 3:38pm » |
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Yes, I use MIDI Yoke NT (Version 1.70 on Windows 2000 Professional SP2).
The task manager shows the CPU load peak in MIDI-OX. If I don't use any MIDI Yoke ports and only send data from my "real" MIDI in to my "real" MIDI out using the MIDI-OX COM interface, I get the problem as well (but I didn't uninstall MIDI Yoke before the test).
I migrated a simple MIDI thru test program from MIDI-OX to another MIDI COM component (MIDI-IO from Mabry Software), so far I have not seen/heard the problem, even in combination with MIDI Yoke.
But as MIDI-IO has only the basic receive / send functionality compared to the wealth of features in MIDI-OX, I am still investigating ...
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Jamie OConnell
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Re: Strange performance problem
« Reply #3 on: Aug 28th, 2001, 10:49pm » |
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on Aug 28th, 2001, 3:38pm, chkk wrote:
If I don't use any MIDI Yoke ports and only send data from my "real" MIDI in to my "real" MIDI out using the MIDI-OX COM interface, I get the problem as well (but I didn't uninstall MIDI Yoke before the test).
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I see. That's good information. I didn't read the first message carefully enough to realize that this was only happening when a script was active. Is this script using a connection point sink, or is it using MIDI polling? We're pretty much at COM's mercy on this either way, but I'm still curious.
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--Jamie
Music is its own reward.
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chkk
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MIDI-OX rules
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Posts: 10
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Re: Strange performance problem
« Reply #4 on: Aug 29th, 2001, 12:29am » |
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on Aug 28th, 2001, 10:49pm, JamieOConnell wrote:
Is this script using a connection point sink, or is it using MIDI polling?
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It is using a connection point sink.
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