[gcc/devel/omp/gcc-12] amdgcn, openmp: Fix concurrency in low-latency allocator

[gcc/devel/omp/gcc-12] amdgcn, openmp: Fix concurrency in low-latency allocator

[Andrew Stubbs]

https://gcc.gnu.org/g:c4116975a5d396f3503b86c0c8cbfe6fffcb146b

commit c4116975a5d396f3503b86c0c8cbfe6fffcb146b
Author: Andrew Stubbs <ams@codesourcery.com>
Date:   Wed Apr 19 17:33:41 2023 +0100

    amdgcn, openmp: Fix concurrency in low-latency allocator
    
    The previous code works fine on Fiji and Vega 10 devices, but bogs down in The
    spin locks on Vega 20 or newer.  Adding the sleep instructions fixes the
    problem.
    
    libgomp/ChangeLog:
    
            * basic-allocator.c (basic_alloc_free): Use BASIC_ALLOC_YIELD.
            (basic_alloc_realloc): Use BASIC_ALLOC_YIELD.

Diff:
---
 libgomp/ChangeLog.omp     | 5 +++++
 libgomp/basic-allocator.c | 2 ++
 2 files changed, 7 insertions(+)

diff --git a/libgomp/ChangeLog.omp b/libgomp/ChangeLog.omp
index 09cf9c6f3c1..32bc3b0c82c 100644
--- a/libgomp/ChangeLog.omp
+++ b/libgomp/ChangeLog.omp
@@ -1,3 +1,8 @@
+2023-04-20  Andrew Stubbs  <ams@codesourcery.com>
+
+	* basic-allocator.c (basic_alloc_free): Use BASIC_ALLOC_YIELD.
+	(basic_alloc_realloc): Use BASIC_ALLOC_YIELD.
+
 2023-04-03  Thomas Schwinge  <thomas@codesourcery.com>
 
 	* target.c (gomp_map_vars_internal)
diff --git a/libgomp/basic-allocator.c b/libgomp/basic-allocator.c
index b4b9e4ba13a..a61828e48a0 100644
--- a/libgomp/basic-allocator.c
+++ b/libgomp/basic-allocator.c
@@ -188,6 +188,7 @@ basic_alloc_free (char *heap, void *addr, size_t size)
 	  break;
 	}
       /* Spin.  */
+      BASIC_ALLOC_YIELD;
     }
   while (1);
 
@@ -267,6 +268,7 @@ basic_alloc_realloc (char *heap, void *addr, size_t oldsize,
 	  break;
 	}
       /* Spin.  */
+      BASIC_ALLOC_YIELD;
     }
   while (1);