[Beignet] thread safety and OpenMP

[Gerald Baier]

Hi Zhigang,

I tried my program with the latest git commit 
(55c85381ceecbb12d4bf8135251c8a3fca4617c0) but the problem still 
persists. Anyway, I'll hack together a minimum example program and 
submit a bug report. Unfortunately I'm currently swamped with work, so 
this might take a while.

Thanks and best regards,
Gerald

On 07/16/2015 08:11 AM, Zhigang Gong wrote:
> Gerald,
>
> Unfortunately, beignet does have some thread-safe bugs, and I recently found and fixed some of them
> Not sure whether these fixes are enough for you, but you can still have a try and let us know the result.
>
> If you can still reproduce the problem, it may be helpful to file a bug at bugzilla and describe how to reproduce
> the issue. The bugzilla link is as below:
> https://bugs.freedesktop.org/enter_bug.cgi?product=Beignet
>
> Thanks,
> Zhigang Gong.
>
>> -----Original Message-----
>> From: Beignet [mailto:beignet-bounces at lists.freedesktop.org] On Behalf Of
>> Gerald Baier
>> Sent: Thursday, July 2, 2015 4:02 AM
>> To: He, Junyan; Song, Ruiling; Gerald Baier; beignet at lists.freedesktop.org
>> Subject: Re: [Beignet] thread safety and OpenMP
>>
>> On 07/01/2015 07:28 AM, He, Junyan wrote:
>>> So far as we know, beignet is thread safe.
>>> Every thead has its own command buffer and do not have relationship
>>> with each others.
>>> Do you use subbuffer to divide the image?
>> No, as far as I can tell I don't use anything special or advanced.
>>> If you can provide some source code or test case, it may help a lot.
>> I'll try to hack together a minimal example over the weekend.
>>
>> Thanks already for your feedback. Cheers.
>>>
>>>
>>> -----Original Message-----
>>> From: Song, Ruiling
>>> Sent: Wednesday, July 01, 2015 10:40 AM
>>> To: Gerald Baier; beignet at lists.freedesktop.org
>>> Cc: He, Junyan
>>> Subject: RE: [Beignet] thread safety and OpenMP
>>>
>>>
>>>
>>>> -----Original Message-----
>>>> From: Beignet [mailto:beignet-bounces at lists.freedesktop.org] On
>>>> Behalf Of Gerald Baier
>>>> Sent: Sunday, June 28, 2015 9:56 PM
>>>> To: beignet at lists.freedesktop.org
>>>> Subject: [Beignet] thread safety and OpenMP
>>>>
>>>> I'm using Beignet for image processing, where basically the image is
>>>> subdivided into tiles which are then processed by several threads
>>>> using OpenMP tasks. I noticed that some of the tiles are occasionally
>>>> messed up. If
>>> Using OpenMP or OpenCL?
>>> Per OpenCL spec, opencl driver should be thread-safe, and Junyan
>> implemented the multi-thread support in beignet. That is to say Beignet is
>> thread-safe.
>>> I am not sure whether Junyan has more comments on how to debug the issue.
>> By the way, if you can provide a test case to reproduce the issue, it would be
>> much helpful.
>>> Thanks!
>>> Ruiling
>>>> I use only one thread everything works fine, also the same program
>>>> runs as expected on nvidia GPUs with multiple threads. Hence the
>>>> question whether Beignet is thread safe and how I could debug my
>> program?
>>>> Here's my configuration:
>>>> device name: Intel(R) HD Graphics IvyBridge M GT2 device version:
>>>> OpenCL
>>>> 1.2 beignet 1.0.3 (git-9e0ca6f)
>>>>
>>>> Best regards,
>>>> Gerald
>>>>
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