Multi-threading

[Michael Gogins]

I've made some changes to csound.c to enable Steven Yi's multi-threading code to run on Windows with our changes to using pthreads internally on all platforms. I've booked these minor changes in. And the code does run.

Unfortunately, there is no significant difference in performance between running with 1 thread and running with 2 threads, so I wonder if this code is actually logically correct. Csound is behaving exactly as if both threads are being scheduled on the same processor (I definitely have 2 processors), so in effect there is only 1 thread with some additional pretend-there-are-threads overhead if the computational load is light.

I've looked at the code and I don't see any problems, but perhaps Steven could could take another look at the logic, run Linux thead statistics commonds on Csound while it is running something heavy, and so on.

In addition, we will need to protect spout and spin to keep from reading or writing junk due to thread contention.

Regards,
Mike







-------------------------------------------------------------------------
Check out the new SourceForge.net Marketplace.
It's the best place to buy or sell services for
just about anything Open Source.
http://sourceforge.net/services/buy/index.php
_______________________________________________
Csound-devel mailing list
Csound-devel@...
https://lists.sourceforge.net/lists/listinfo/csound-devel

[Steven Yi]

Hi Michael,

I'll try to take a look when I can but I've got a big deadline at my
job on Monday so probably won't be until mid-week.

Thanks!
steven

On Sat, Jun 14, 2008 at 12:10 PM, Michael Gogins <gogins@...> wrote:

> I've made some changes to csound.c to enable Steven Yi's multi-threading code to run on Windows with our changes to using pthreads internally on all platforms. I've booked these minor changes in. And the code does run.
>
> Unfortunately, there is no significant difference in performance between running with 1 thread and running with 2 threads, so I wonder if this code is actually logically correct. Csound is behaving exactly as if both threads are being scheduled on the same processor (I definitely have 2 processors), so in effect there is only 1 thread with some additional pretend-there-are-threads overhead if the computational load is light.
>
> I've looked at the code and I don't see any problems, but perhaps Steven could could take another look at the logic, run Linux thead statistics commonds on Csound while it is running something heavy, and so on.
>
> In addition, we will need to protect spout and spin to keep from reading or writing junk due to thread contention.
>
> Regards,
> Mike
>
>
>
>
>
>
>
> -------------------------------------------------------------------------
> Check out the new SourceForge.net Marketplace.
> It's the best place to buy or sell services for
> just about anything Open Source.
> http://sourceforge.net/services/buy/index.php
> _______________________________________________
> Csound-devel mailing list
> Csound-devel@...
> https://lists.sourceforge.net/lists/listinfo/csound-devel
>

-------------------------------------------------------------------------
Check out the new SourceForge.net Marketplace.
It's the best place to buy or sell services for
just about anything Open Source.
http://sourceforge.net/services/buy/index.php
_______________________________________________
Csound-devel mailing list
Csound-devel@...
https://lists.sourceforge.net/lists/listinfo/csound-devel

[Felipe Sateler]

Running with --num-threads=x with x > 1 makes csound hang before producing any
sound output. It seems to be a deadlock because no cpu is being used. This is
a linux system, with current cvs.

El 15/06/08 13:30 Michael Gogins escribió:

> I've made some changes to csound.c to enable Steven Yi's multi-threading
> code to run on Windows with our changes to using pthreads internally on all
> platforms. I've booked these minor changes in. And the code does run.
>
> Unfortunately, there is no significant difference in performance between
> running with 1 thread and running with 2 threads, so I wonder if this code
> is actually logically correct. Csound is behaving exactly as if both
> threads are being scheduled on the same processor (I definitely have 2
> processors), so in effect there is only 1 thread with some additional
> pretend-there-are-threads overhead if the computational load is light.
>
> I've looked at the code and I don't see any problems, but perhaps Steven
> could could take another look at the logic, run Linux thead statistics
> commonds on Csound while it is running something heavy, and so on.
>
> In addition, we will need to protect spout and spin to keep from reading or
> writing junk due to thread contention.
>
> Regards,
> Mike
>
>
>
>
>
>
>
> -------------------------------------------------------------------------
> Check out the new SourceForge.net Marketplace.
> It's the best place to buy or sell services for
> just about anything Open Source.
> http://sourceforge.net/services/buy/index.php
> _______________________________________________
> Csound-devel mailing list
> Csound-devel@...
> https://lists.sourceforge.net/lists/listinfo/csound-devel

--
Saludos,
Felipe Sateler


-------------------------------------------------------------------------
Check out the new SourceForge.net Marketplace.
It's the best place to buy or sell services for
just about anything Open Source.
http://sourceforge.net/services/buy/index.php
_______________________________________________
Csound-devel mailing list
Csound-devel@...
https://lists.sourceforge.net/lists/listinfo/csound-devel

[Steven Yi]

I just gave it a try here and it seems awfully slow here too.  I can't
say I have a clue at the moment as to why, and unfortunately am about
to go away for a week so won't be able to look into it until after
next Friday. My guess is that we just have a lot of work to do!

On Sun, Jun 15, 2008 at 10:32 AM, Felipe Sateler <fsateler@...> wrote:

> Running with --num-threads=x with x > 1 makes csound hang before producing any
> sound output. It seems to be a deadlock because no cpu is being used. This is
> a linux system, with current cvs.
>
> El 15/06/08 13:30 Michael Gogins escribió:
>> I've made some changes to csound.c to enable Steven Yi's multi-threading
>> code to run on Windows with our changes to using pthreads internally on all
>> platforms. I've booked these minor changes in. And the code does run.
>>
>> Unfortunately, there is no significant difference in performance between
>> running with 1 thread and running with 2 threads, so I wonder if this code
>> is actually logically correct. Csound is behaving exactly as if both
>> threads are being scheduled on the same processor (I definitely have 2
>> processors), so in effect there is only 1 thread with some additional
>> pretend-there-are-threads overhead if the computational load is light.
>>
>> I've looked at the code and I don't see any problems, but perhaps Steven
>> could could take another look at the logic, run Linux thead statistics
>> commonds on Csound while it is running something heavy, and so on.
>>
>> In addition, we will need to protect spout and spin to keep from reading or
>> writing junk due to thread contention.
>>
>> Regards,
>> Mike
>>
>>
>>
>>
>>
>>
>>
>> -------------------------------------------------------------------------
>> Check out the new SourceForge.net Marketplace.
>> It's the best place to buy or sell services for
>> just about anything Open Source.
>> http://sourceforge.net/services/buy/index.php
>> _______________________________________________
>> Csound-devel mailing list
>> Csound-devel@...
>> https://lists.sourceforge.net/lists/listinfo/csound-devel
>
>
>
> --
> Saludos,
> Felipe Sateler
>
> -------------------------------------------------------------------------
> Check out the new SourceForge.net Marketplace.
> It's the best place to buy or sell services for
> just about anything Open Source.
> http://sourceforge.net/services/buy/index.php
> _______________________________________________
> Csound-devel mailing list
> Csound-devel@...
> https://lists.sourceforge.net/lists/listinfo/csound-devel
>
>

-------------------------------------------------------------------------
Check out the new SourceForge.net Marketplace.
It's the best place to buy or sell services for
just about anything Open Source.
http://sourceforge.net/services/buy/index.php
_______________________________________________
Csound-devel mailing list
Csound-devel@...
https://lists.sourceforge.net/lists/listinfo/csound-devel