RE: [PATCH] drm/i915: check to see if SIMD registers are available before using SIMD

2020-05-04 Thread David Laight
From: Christoph Hellwig > Sent: 04 May 2020 17:03 > > On Sun, May 03, 2020 at 09:20:19PM +0100, Chris Wilson wrote: > > > Err, why does i915 implements its own uncached memcpy instead of relying > > > on core functionality to start with? > > > > What is this core functionality that provides

Re: [PATCH] drm/i915: check to see if SIMD registers are available before using SIMD

2020-05-04 Thread Christoph Hellwig
On Sun, May 03, 2020 at 09:20:19PM +0100, Chris Wilson wrote: > > Err, why does i915 implements its own uncached memcpy instead of relying > > on core functionality to start with? > > What is this core functionality that provides movntqda? A sensible name might be memcpy_uncached or

Re: [PATCH] drm/i915: check to see if SIMD registers are available before using SIMD

2020-05-03 Thread Jason A. Donenfeld
On Sun, May 3, 2020 at 2:30 PM Chris Wilson wrote: > > Quoting Jason A. Donenfeld (2020-04-30 23:10:16) > > Sometimes it's not okay to use SIMD registers, the conditions for which > > have changed subtly from kernel release to kernel release. Usually the > > pattern is to check for may_use_simd()

Re: [PATCH] drm/i915: check to see if SIMD registers are available before using SIMD

2020-05-03 Thread Chris Wilson
Quoting Jason A. Donenfeld (2020-04-30 23:10:16) > Sometimes it's not okay to use SIMD registers, the conditions for which > have changed subtly from kernel release to kernel release. Usually the > pattern is to check for may_use_simd() and then fallback to using > something slower in the unlikely

Re: [PATCH] drm/i915: check to see if SIMD registers are available before using SIMD

2020-05-03 Thread Chris Wilson
Quoting Christoph Hellwig (2020-05-01 19:07:31) > On Thu, Apr 30, 2020 at 04:10:16PM -0600, Jason A. Donenfeld wrote: > > Sometimes it's not okay to use SIMD registers, the conditions for which > > have changed subtly from kernel release to kernel release. Usually the > > pattern is to check for

Re: [PATCH] drm/i915: check to see if SIMD registers are available before using SIMD

2020-05-01 Thread Jason A. Donenfeld
On Fri, May 1, 2020 at 12:07 PM Christoph Hellwig wrote: > > On Thu, Apr 30, 2020 at 04:10:16PM -0600, Jason A. Donenfeld wrote: > > Sometimes it's not okay to use SIMD registers, the conditions for which > > have changed subtly from kernel release to kernel release. Usually the > > pattern is to

Re: [PATCH] drm/i915: check to see if SIMD registers are available before using SIMD

2020-05-01 Thread Jason A. Donenfeld
On Fri, May 1, 2020 at 4:42 AM Sebastian Andrzej Siewior wrote: >Reviewed-by: Sebastian Andrzej Siewior Thanks. > > May I ask how large the memcpy can be? I'm asking in case it is large > and an explicit rescheduling point might be needed. Yea I was worried about that too. I'm not an i915

Re: [PATCH] drm/i915: check to see if SIMD registers are available before using SIMD

2020-05-01 Thread Christoph Hellwig
On Thu, Apr 30, 2020 at 04:10:16PM -0600, Jason A. Donenfeld wrote: > Sometimes it's not okay to use SIMD registers, the conditions for which > have changed subtly from kernel release to kernel release. Usually the > pattern is to check for may_use_simd() and then fallback to using > something

RE: [PATCH] drm/i915: check to see if SIMD registers are available before using SIMD

2020-05-01 Thread David Laight
From: Sebastian Andrzej Siewior > Sent: 01 May 2020 11:42 > On 2020-04-30 16:10:16 [-0600], Jason A. Donenfeld wrote: > > Sometimes it's not okay to use SIMD registers, the conditions for which > > have changed subtly from kernel release to kernel release. Usually the > > pattern is to check for

Re: [PATCH] drm/i915: check to see if SIMD registers are available before using SIMD

2020-05-01 Thread Sebastian Andrzej Siewior
On 2020-04-30 16:10:16 [-0600], Jason A. Donenfeld wrote: > Sometimes it's not okay to use SIMD registers, the conditions for which > have changed subtly from kernel release to kernel release. Usually the > pattern is to check for may_use_simd() and then fallback to using > something slower in the

[PATCH] drm/i915: check to see if SIMD registers are available before using SIMD

2020-04-30 Thread Jason A. Donenfeld
Sometimes it's not okay to use SIMD registers, the conditions for which have changed subtly from kernel release to kernel release. Usually the pattern is to check for may_use_simd() and then fallback to using something slower in the unlikely case SIMD registers aren't available. So, this patch