[Starpu-devel] StarPU 1.2.3 - Serious bug in OpenCL

[Alexander Grund <alexander.grund@tu-dresden.de>]

Dear StarPU developers,

I'm evaluating StarPU 1.2.3 and found a show-stopper bug in the OpenCL 
backend:

When running the simple axpy example on OpenCL GPUs one runs into a 
deadlock cause by the following: Buffer transfers are enqueued and the 
corresponding event is recorded. Later this event is queried until it 
signals completion. However the action is never flushed to the device, 
which requires 'clFlush'. Hence the events status is CL_QUEUED and never 
changes.

Using synchronous transfers or execution (e.g. with *_PIPELINE_LENGTH=0) 
a 'clWait' is executed which implicitly calls 'clFlush'  and hence does 
not lead to the deadlock. But that is obviously not a solution.

Furthermore a few of the links on the downloads section are broken. 
Basically 5 of the 6 "nightly snapshot" links (linux leads to HTTP 404 
and windows to a jenkins login) and the "Coverage" link of 1.2.3 (typo 
in the link: it has an extra "2")

Best Regards,
Alexander Grund

--
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Technische Universitaet Dresden
Zentrum für Informationsdienste und Hochleistungsrechnen (ZIH)
Verteiltes und Datenintensives Rechnen (VDR)
Dipl.-Ing. Alexander Grund
Chemnitzer Str. 46b, Raum 243 01062 Dresden
Tel.: +49 351 463-35982
E-Mail: alexander.grund@tu-dresden.de
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