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{ "id": 2233013, "url": "http://patchwork.ozlabs.org/api/1.2/covers/2233013/?format=api", "web_url": "http://patchwork.ozlabs.org/project/gcc/cover/20260505134929.3522938-1-aarsenovic@baylibre.com/", "project": { "id": 17, "url": "http://patchwork.ozlabs.org/api/1.2/projects/17/?format=api", "name": "GNU Compiler Collection", "link_name": "gcc", "list_id": "gcc-patches.gcc.gnu.org", "list_email": "gcc-patches@gcc.gnu.org", "web_url": null, "scm_url": null, "webscm_url": null, "list_archive_url": "", "list_archive_url_format": "", "commit_url_format": "" }, "msgid": "<20260505134929.3522938-1-aarsenovic@baylibre.com>", "list_archive_url": null, "date": "2026-05-05T13:14:56", "name": "[0/4] GCN: Target offload overhead improvements, batch 2", "submitter": { "id": 92125, "url": "http://patchwork.ozlabs.org/api/1.2/people/92125/?format=api", "name": "Arsen Arsenović", "email": "aarsenovic@baylibre.com" }, "mbox": "http://patchwork.ozlabs.org/project/gcc/cover/20260505134929.3522938-1-aarsenovic@baylibre.com/mbox/", "series": [ { "id": 502845, "url": "http://patchwork.ozlabs.org/api/1.2/series/502845/?format=api", "web_url": "http://patchwork.ozlabs.org/project/gcc/list/?series=502845", "date": "2026-05-05T13:14:59", "name": "GCN: Target offload overhead improvements, batch 2", "version": 1, "mbox": "http://patchwork.ozlabs.org/series/502845/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/covers/2233013/comments/", "headers": { "Return-Path": "<gcc-patches-bounces~incoming=patchwork.ozlabs.org@gcc.gnu.org>", "X-Original-To": [ "incoming@patchwork.ozlabs.org", "gcc-patches@gcc.gnu.org" ], "Delivered-To": [ "patchwork-incoming@legolas.ozlabs.org", "gcc-patches@gcc.gnu.org" ], "Authentication-Results": [ "legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=baylibre-com.20251104.gappssmtp.com\n header.i=@baylibre-com.20251104.gappssmtp.com header.a=rsa-sha256\n header.s=20251104 header.b=Ni7hDO/K;\n\tdkim-atps=neutral", "legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=gcc.gnu.org\n (client-ip=2620:52:6:3111::32; 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charset=UTF-8", "Content-Transfer-Encoding": "8bit", "X-BeenThere": "gcc-patches@gcc.gnu.org", "X-Mailman-Version": "2.1.30", "Precedence": "list", "List-Id": "Gcc-patches mailing list <gcc-patches.gcc.gnu.org>", "List-Unsubscribe": "<https://gcc.gnu.org/mailman/options/gcc-patches>,\n <mailto:gcc-patches-request@gcc.gnu.org?subject=unsubscribe>", "List-Archive": "<https://gcc.gnu.org/pipermail/gcc-patches/>", "List-Post": "<mailto:gcc-patches@gcc.gnu.org>", "List-Help": "<mailto:gcc-patches-request@gcc.gnu.org?subject=help>", "List-Subscribe": "<https://gcc.gnu.org/mailman/listinfo/gcc-patches>,\n <mailto:gcc-patches-request@gcc.gnu.org?subject=subscribe>", "Errors-To": "gcc-patches-bounces~incoming=patchwork.ozlabs.org@gcc.gnu.org" }, "content": "Hi!\n\nThis patch series further reduces overhead of launching kernels on GCN\ndevices on top of the already-landed patches, by removing a redundant\nallocation and reducing the overhead of constructing the target variable\ntable (the table of addresses of mapped variables in device memory) by\nmoving it into host memory and kernel arguments. This then piggy-backs\noff of the kernel argument cache previously added to avoid allocating a\nnew target variable table in most cases.\n\nIt also introduces the concept of \"offload sessions\", that can be\nfurther expanded in the future, to carry the state required to start a\ntarget region.\n\nThis reduces the overhead of launching a kernel by ~27%.\n\nThe series also reduces the overhead of launching threads on the actual\nGCN device, by parallelizing thread initialization, akin to what the\npatch proposed by Matthew Malcomson does here:\nhttps://inbox.sourceware.org/gcc-patches/20251126131142.644866-6-mmalcomson@nvidia.com/\n\nArsen Arsenović (4):\n libgomp/gcn: parallelize initializing threads of a team\n libgomp: let plugins handle allocating the target variable table\n libgomp/plugin-gcn: remove unneeded heap allocation in run_kernel\n libgomp/oacc-mem: add missing assert to goacc_enter_datum\n\n include/gomp-constants.h | 2 +-\n libgomp/config/gcn/team.c | 121 ++++---\n libgomp/libgomp-plugin.h | 81 ++++-\n libgomp/libgomp.h | 58 +++-\n libgomp/oacc-host.c | 63 +++-\n libgomp/oacc-mem.c | 11 +-\n libgomp/oacc-parallel.c | 24 +-\n libgomp/plugin/plugin-gcn.c | 310 ++++++++++++------\n libgomp/plugin/plugin-nvptx.c | 45 ++-\n libgomp/target.c | 191 +++++++----\n libgomp/task.c | 33 +-\n .../gcn-kernel-launch-no-tvt-alloc.c | 51 +++\n .../gcn-kernel-launch-tvt-alloc.c | 16 +\n 13 files changed, 750 insertions(+), 256 deletions(-)\n create mode 100644 libgomp/testsuite/libgomp.c-c++-common/gcn-kernel-launch-no-tvt-alloc.c\n create mode 100644 libgomp/testsuite/libgomp.c-c++-common/gcn-kernel-launch-tvt-alloc.c" }