Re: [PATCH] libgomp, OpenMP, nvptx: Low-latency memory allocator

[Andrew Stubbs <ams@codesourcery.com>]

On 05/01/2022 13:04, Tom de Vries wrote:
> On 1/5/22 12:08, Tom de Vries wrote:
>> The allocators-1.c test-case doesn't compile because:
>> ...
>> FAIL: libgomp.c/allocators-1.c (test for excess errors)
>> Excess errors:
>> /home/vries/oacc/trunk/source-gcc/libgomp/testsuite/libgomp.c/allocators-1.c:7:22: 
>> sorry, unimplemented: '    ' clause on 'requires' directive not 
>> supported yet
>>
>> UNRESOLVED: libgomp.c/allocators-1.c compilation failed to produce 
>> executable
>> ...
>>
>> So, I suppose I need "[PATCH] OpenMP front-end: allow requires 
>> dynamic_allocators" as well, I'll try again with that applied.
> 
> After applying that, I get:
> ...
> WARNING: program timed out.
> FAIL: libgomp.c/allocators-2.c execution test
> WARNING: program timed out.
> FAIL: libgomp.c/allocators-3.c execution test
> ...

It works for me.....

Those tests are doing some large number of allocations repeatedly and in 
parallel to stress the atomics. They're also slightly longer running 
than the other tests.
   - allocators-2 calls omp_alloc 8080 times, over 16 kernel launches, 
some of which will fall back to PTX malloc.
   - allocators-3 calls omp_alloc and omp_free 8 million times each, 
over 8 kernel launches, and takes about a minute to run on my device 
(whether that falls back depends entirely on how the free calls interleave).

Either there is a flaw in the concurrency causing some kind of deadlock, 
or else your timeout is set too short for your device. I hope it's the 
latter. We may need to tweak this.

Andrew