Cog vs CogMT?

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Cog vs CogMT?

Paul DeBruicker
Hi -

When should the multi-threaded version of Cog be used vs the single
threaded version? Is either one more stable or performant, etc?

Thanks

Paul

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Re: Cog vs CogMT?

Mariano Martinez Peck


On Fri, Oct 21, 2011 at 7:12 PM, Paul DeBruicker <[hidden email]> wrote:
Hi -

When should the multi-threaded version of Cog be used vs the single threaded version? Is either one more stable or performant, etc?


The MT of Cog is only for FFI as much as I understand. The VM itself continues to be a green thread, even with CogMT. So no, there is not performance change, only in FFI.
That being said, I never hear someone apart from Eliot successfully using CogMT with real multithreaded FFI. There may be some work still to do before you can use it.
 
Thanks

Paul




--
Mariano
http://marianopeck.wordpress.com

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Re: Cog vs CogMT?

Igor Stasenko
On 21 October 2011 21:24, Mariano Martinez Peck <[hidden email]> wrote:

>
>
> On Fri, Oct 21, 2011 at 7:12 PM, Paul DeBruicker <[hidden email]> wrote:
>>
>> Hi -
>>
>> When should the multi-threaded version of Cog be used vs the single
>> threaded version? Is either one more stable or performant, etc?
>>
>
> The MT of Cog is only for FFI as much as I understand. The VM itself
> continues to be a green thread, even with CogMT. So no, there is not
> performance change, only in FFI.
> That being said, I never hear someone apart from Eliot successfully using
> CogMT with real multithreaded FFI. There may be some work still to do before
> you can use it.
>

I plan to change the VMs on Jenkins server to build using MT version
of (co)interpreter.

I misunderstood Eliot's statement once, when he said that MT version
of  VM is 5% slower,
but then Eliot clarified that this slowdown related only to FFI, not
the whole VM.


--
Best regards,
Igor Stasenko.

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Re: Cog vs CogMT?

Stéphane Ducasse
Thanks igor

yes indeed this is important.

Stef

>>>
>>> Hi -
>>>
>>> When should the multi-threaded version of Cog be used vs the single
>>> threaded version? Is either one more stable or performant, etc?
>>>
>>
>> The MT of Cog is only for FFI as much as I understand. The VM itself
>> continues to be a green thread, even with CogMT. So no, there is not
>> performance change, only in FFI.
>> That being said, I never hear someone apart from Eliot successfully using
>> CogMT with real multithreaded FFI. There may be some work still to do before
>> you can use it.
>>
>
> I plan to change the VMs on Jenkins server to build using MT version
> of (co)interpreter.
>
> I misunderstood Eliot's statement once, when he said that MT version
> of  VM is 5% slower,
> but then Eliot clarified that this slowdown related only to FFI, not
> the whole VM.
>
>
> --
> Best regards,
> Igor Stasenko.
>