[og12] libgomp: Document OpenMP 'pinned' memory (was: [PATCH] libgomp, openmp: pinned memory

[Thomas Schwinge <thomas@codesourcery.com>]

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Hi!

On 2022-01-04T15:32:17+0000, Andrew Stubbs <ams@codesourcery.com> wrote:
> This patch implements the OpenMP pinned memory trait [...]

I figure it may be helpful to document the current og12 state of affairs;
does the attached "libgomp: Document OpenMP 'pinned' memory" look good to
you?


Grüße
 Thomas


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From 35ac1fb2d37f6c33a69f85ca8bac6f6a7bd7d837 Mon Sep 17 00:00:00 2001
From: Thomas Schwinge <thomas@codesourcery.com>
Date: Fri, 24 Mar 2023 15:14:57 +0100
Subject: [PATCH] libgomp: Document OpenMP 'pinned' memory

	libgomp/
	* libgomp.texi (AMD Radeon, nvptx): Document OpenMP 'pinned'
	memory.
---
 libgomp/libgomp.texi | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/libgomp/libgomp.texi b/libgomp/libgomp.texi
index 288e0b3a8ea..1cfae0cb8d1 100644
--- a/libgomp/libgomp.texi
+++ b/libgomp/libgomp.texi
@@ -4456,6 +4456,9 @@ The implementation remark:
 @item OpenMP code that has a requires directive with @code{unified_address} or
       @code{unified_shared_memory} will remove any GCN device from the list of
       available devices (``host fallback'').
+@item OpenMP @emph{pinned} memory (@code{omp_atk_pinned},
+      @code{ompx_pinned_mem_alloc}, for example) is allocated not via
+      the device, but via @code{mmap}, @code{mlock}.
 @end itemize
 
 
@@ -4518,6 +4521,10 @@ The implementation remark:
 @item OpenMP code that has a requires directive with @code{unified_address}
       or @code{unified_shared_memory} will remove any nvptx device from the
       list of available devices (``host fallback'').
+@item OpenMP @emph{pinned} memory (@code{omp_atk_pinned},
+      @code{ompx_pinned_mem_alloc}, for example) is allocated via the
+      device, thus helping lower-overhead host <-> device data
+      transfers.
 @end itemize
 
 
-- 
2.25.1