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* [PATCH] amdgcn: remove unnecessary scalar cache flush
@ 2023-10-20 11:54 Andrew Stubbs
  2023-10-31 11:26 ` Andrew Stubbs
  2023-10-31 12:39 ` Corinna Vinschen
  0 siblings, 2 replies; 3+ messages in thread
From: Andrew Stubbs @ 2023-10-20 11:54 UTC (permalink / raw)
  To: newlib

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Hi,

This patch is necessary to support AMD RDNA2 GPUs that don't have a 
writable scalar cache.  However, the write back isn't actually doing 
anything useful on any GPU any more, so we can remove it.

Andrew

[-- Attachment #2: 231020-newlib-remove-s_dcache_wb.patch --]
[-- Type: text/plain, Size: 555 bytes --]

amdgcn: remove unnecessary scalar cache flush

The exit code isn't actually written via the scalar cache so the cache flush
is not actually needed.

diff --git a/newlib/libc/machine/amdgcn/exit-value.h b/newlib/libc/machine/amdgcn/exit-value.h
index 7aa2508bb..6b9d2411b 100644
--- a/newlib/libc/machine/amdgcn/exit-value.h
+++ b/newlib/libc/machine/amdgcn/exit-value.h
@@ -32,7 +32,6 @@ exit_with_int (int val)
   *return_value = val;
 
   /* Terminate the current kernel.  */
-  asm ("s_dcache_wb");
   asm ("s_endpgm");
   __builtin_unreachable ();
 }

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] amdgcn: remove unnecessary scalar cache flush
  2023-10-20 11:54 [PATCH] amdgcn: remove unnecessary scalar cache flush Andrew Stubbs
@ 2023-10-31 11:26 ` Andrew Stubbs
  2023-10-31 12:39 ` Corinna Vinschen
  1 sibling, 0 replies; 3+ messages in thread
From: Andrew Stubbs @ 2023-10-31 11:26 UTC (permalink / raw)
  To: newlib

Ping.

On 20/10/2023 12:54, Andrew Stubbs wrote:
> Hi,
> 
> This patch is necessary to support AMD RDNA2 GPUs that don't have a 
> writable scalar cache.  However, the write back isn't actually doing 
> anything useful on any GPU any more, so we can remove it.
> 
> Andrew


^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] amdgcn: remove unnecessary scalar cache flush
  2023-10-20 11:54 [PATCH] amdgcn: remove unnecessary scalar cache flush Andrew Stubbs
  2023-10-31 11:26 ` Andrew Stubbs
@ 2023-10-31 12:39 ` Corinna Vinschen
  1 sibling, 0 replies; 3+ messages in thread
From: Corinna Vinschen @ 2023-10-31 12:39 UTC (permalink / raw)
  To: newlib

On Oct 20 12:54, Andrew Stubbs wrote:
> Hi,
> 
> This patch is necessary to support AMD RDNA2 GPUs that don't have a writable
> scalar cache.  However, the write back isn't actually doing anything useful
> on any GPU any more, so we can remove it.
> 
> Andrew

> amdgcn: remove unnecessary scalar cache flush
> 
> The exit code isn't actually written via the scalar cache so the cache flush
> is not actually needed.
> 
> diff --git a/newlib/libc/machine/amdgcn/exit-value.h b/newlib/libc/machine/amdgcn/exit-value.h
> index 7aa2508bb..6b9d2411b 100644
> --- a/newlib/libc/machine/amdgcn/exit-value.h
> +++ b/newlib/libc/machine/amdgcn/exit-value.h
> @@ -32,7 +32,6 @@ exit_with_int (int val)
>    *return_value = val;
>  
>    /* Terminate the current kernel.  */
> -  asm ("s_dcache_wb");
>    asm ("s_endpgm");
>    __builtin_unreachable ();
>  }

Pushed.

Thanks,
Corinna


^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2023-10-31 12:39 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2023-10-20 11:54 [PATCH] amdgcn: remove unnecessary scalar cache flush Andrew Stubbs
2023-10-31 11:26 ` Andrew Stubbs
2023-10-31 12:39 ` Corinna Vinschen

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