[Mesa-dev] [PATCH 00/13] Implement INTEL_shader_atomic_float_minmax
idr at freedesktop.org
Tue Aug 21 16:19:48 UTC 2018
On 08/21/2018 06:10 AM, Axel Davy wrote:
> On 23/06/2018 07:03, Ian Romanick wrote:
>> I initially started implementing support for NV_shader_atomic_float. I
>> had misunderstood the hardware specs, and Intel hardware cannot actually
>> do that extension. It does have some floating-point atomic support, so
>> I decided to create an extension based on what the hardware actually can
>> do. I discussed this with some guys at AMD and NVIDIA, and it seems
>> nobody else can do these things.
> Older AMD SI chips had the functionality, as can be seen here:
> It features BUFFER_ATOMIC_FMIN, BUFFER_ATOMIC_FCMPSWAP and
> The feature seems to have been dropped with later iterations of GCN.
Yeah, that's basically what Marek told me on IRC.
> Reading the spec of intel broadwell, there are some sections mentioning
> atomic float add,
> But there is no mention of it for Skylake. Maybe it was supported, but
> dropped ?
That bit of documentation is the reason I started working on the NV
extension. As far as I can tell, the feature was planned, but it was
never implemented. I spent a whole day trying to figure out why I was
hanging the GPU before I realized it was because the hardware did not
support that feature. :(
> Axel Davy
More information about the mesa-dev