[gcc/devel/omp/gcc-13] amdgcn, openmp: Fix concurrency in low-latency allocator

[gcc/devel/omp/gcc-13] amdgcn, openmp: Fix concurrency in low-latency allocator

[Kwok Yeung]

https://gcc.gnu.org/g:5410e14552bcf400633556b563a90f6f2e00727e

commit 5410e14552bcf400633556b563a90f6f2e00727e
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 d98ca622634..65a5d97e522 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 afddc79cf75..167acee94fb 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);