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OpenCL

alazaro
Adept II

Re: Maximum Number of Commands Queues in AMD GPU?

Hi,

I´ve checked a scenario where 2 contexts are created. For each context, I´ve created 64 commands queues. 64 is less than 69 for each context, but the total sum of both contexts is higher than 69. The program continues to crash when 69 commands queues are created overall. Addiotinally, I've changed the parameter GPU_MAX_COMMAND_QUEUES with the command: export GPU_MAX_COMMAND_QUEUES=128 , but I haven't had success.

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alazaro
Adept II

Re: Maximum Number of Commands Queues in AMD GPU?

Hi nibal, I´ve checked syslog but I haven´t seen anything strange.

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nibal
Challenger

Re: Maximum Number of Commands Queues in AMD GPU?

I wrote this b4 you tested it on a different system. Was looking for a hardware problem, but the chance of the same thing happening in 2 different system is none. Plz ignore.

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dipak
Staff
Staff

Re: Maximum Number of Commands Queues in AMD GPU?

Yes, as I checked on multiple GPUs, the number of max. command queues seems constant. Also,  indeed there is no effect of .GPU_MAX_COMMAND_QUEUES.

I guess, someone from runtime team may provide better insights in this regard. I'll check and get back to you.

dipak
Staff
Staff

Re: Maximum Number of Commands Queues in AMD GPU?

Sorry for this delayed reply.

As I've come to know that indeed the number of max. host-side command queues is a hard limit and it is currently set to 70 per-process (69 with a zero based counting). So, the above observation was reasonable.

Regards,

nibal
Challenger

Re: Maximum Number of Commands Queues in AMD GPU?

dipak wrote:

Sorry for this delayed reply.

As I've come to know that indeed the number of max. host-side command queues is a hard limit and it is currently set to 70 per-process (69 with a zero based counting). So, the above observation was reasonable.

Regards,

Hmm. So the error code CL_OUT_OF_RESOURCES is correct in this case. We assumed wrongly it was memory, when in fact it was number of queues 😞

alazaro
Adept II

Re: Maximum Number of Commands Queues in AMD GPU?

Hi dipak !! Don´t worry. Thank you so much for your reply.

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alazaro
Adept II

Re: Maximum Number of Commands Queues in AMD GPU?

Hi dipak !! thank you for your help as well. :-).

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alazaro
Adept II

Re: Maximum Number of Commands Queues in AMD GPU?

Hi dipak, excuse me for the delay of this question. Do you know any document where the statement about the limit of command queues per-process is reported?. Your statement is truth but now I am writting an article and I have to write a reference for this.

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dipak
Staff
Staff

Re: Maximum Number of Commands Queues in AMD GPU?

Sorry, I'm not aware of any such. I came to know that information from relevant team.

AFAIK, the limit is there because the OCL conformance test expects a predictable amount of queues. The limit is implementation dependent and may vary in future. So, I've doubt that there is any such document publicly available.

Regards,