Hi! On 2024-07-15T17:01:46+0100, Andrew Stubbs <a...@baylibre.com> wrote: > On 15/07/2024 16:36, Thomas Schwinge wrote: >> On 2024-07-15T12:16:30+0100, Andrew Stubbs <a...@baylibre.com> wrote: >>> On 15/07/2024 10:29, Thomas Schwinge wrote: >>>> On 2021-11-12T18:58:04+0100, Jakub Jelinek via Gcc-patches >>>> <gcc-patches@gcc.gnu.org> wrote: >>>>> And finally here is a third version, [...] >>>> >>>> ... which became commit 9fa72756d90e0d9edadf6e6f5f56476029925788 >>>> "libgomp, nvptx: Honor OpenMP 5.1 num_teams lower bound". >>>> >>>> Attached here is "GCN: Honor OpenMP 5.1 'num_teams' lower bound", which >>>> are exactly the corresponding changes for GCN (see below Jakub's nvptx >>>> changes for reference); OK to push? >> >>> That's a lot of convoluted logic to drop in without a single comment! >> >> Well, I'll pass that compliment over to Jakub ;-) -- my code changes just >> intend to be a faithful "'s%nvptx%GCN'" of his code changes from back >> then. >> >>> The GCN bits look fine, and I assume you've probably thought about the >>> logic here a lot, but I've no idea what you're trying to achieve, or why >>> you're trying to achieve it (from the patch alone). >>> >>> Can we have some comments on motivation and goals, please? >> >> Here's the original context: >> >> - <https://inbox.sourceware.org/20211111190313.GV2710@tucnak> "[PATCH] >> openmp: Honor OpenMP 5.1 num_teams lower bound" >> - <https://inbox.sourceware.org/20211112132023.GC2710@tucnak> "[PATCH] >> libgomp, nvptx: Honor OpenMP 5.1 num_teams lower bound" >> >> Is that sufficient, and/or would you like to see some commentary to the >> relevant libgomp generic/nvptx/GCN code added? > > Yes, sorry if it wasn't clear; I meant *code* comments. > > /* The team number is usually the same as the gcn_dim_pos(0), except > when num_teams(N) is ..... */ > > The FIXME actually tells me something useful about one of the > conditional cases, but that's being removed here. > > Also, why are we returning "false" in other cases, and what effect does > that have? Is that for "spare" teams when we launch more than we need?
How about the attached "libgomp: Document 'GOMP_teams4'"? Jakub, does that accurately reflect the relevant facts? Grüße Thomas
>From 149c2dc71bb44a9365ea3c360304f75cb9056084 Mon Sep 17 00:00:00 2001 From: Thomas Schwinge <tschwi...@baylibre.com> Date: Tue, 16 Jul 2024 17:09:38 +0200 Subject: [PATCH] libgomp: Document 'GOMP_teams4' For reference: - <https://inbox.sourceware.org/20211111190313.GV2710@tucnak> "[PATCH] openmp: Honor OpenMP 5.1 num_teams lower bound" - <https://inbox.sourceware.org/20211112132023.GC2710@tucnak> "[PATCH] libgomp, nvptx: Honor OpenMP 5.1 num_teams lower bound" libgomp/ * config/gcn/target.c (GOMP_teams4): Document. * config/nvptx/target.c (GOMP_teams4): Likewise. * target.c (GOMP_teams4): Likewise. --- libgomp/config/gcn/target.c | 8 ++++++++ libgomp/config/nvptx/target.c | 8 ++++++++ libgomp/target.c | 9 +++++++++ 3 files changed, 25 insertions(+) diff --git a/libgomp/config/gcn/target.c b/libgomp/config/gcn/target.c index e57d2e5f93f..9cafea4e2cc 100644 --- a/libgomp/config/gcn/target.c +++ b/libgomp/config/gcn/target.c @@ -29,6 +29,14 @@ extern volatile struct gomp_offload_icvs GOMP_ADDITIONAL_ICVS; +/* Implement OpenMP 'teams' construct. + + Initialize upon FIRST call. Return whether this invocation is active. + Depending on whether NUM_TEAMS_LOWER asks for more teams than are provided + in hardware, we may need to loop multiple times; in that case make sure to + update the team-level variable used by 'omp_get_team_num', as we then can't + just use '__builtin_gcn_dim_pos (0)'. */ + bool GOMP_teams4 (unsigned int num_teams_lower, unsigned int num_teams_upper, unsigned int thread_limit, bool first) diff --git a/libgomp/config/nvptx/target.c b/libgomp/config/nvptx/target.c index f14dcfc8ff6..8d4dc5f661a 100644 --- a/libgomp/config/nvptx/target.c +++ b/libgomp/config/nvptx/target.c @@ -31,6 +31,14 @@ extern int __gomp_team_num __attribute__((shared)); extern volatile struct gomp_offload_icvs GOMP_ADDITIONAL_ICVS; volatile struct rev_offload *GOMP_REV_OFFLOAD_VAR; +/* Implement OpenMP 'teams' construct. + + Initialize upon FIRST call. Return whether this invocation is active. + Depending on whether NUM_TEAMS_LOWER asks for more teams than are provided + in hardware, we may need to loop multiple times; in that case make sure to + update the team-level variable used by 'omp_get_team_num', as we then can't + just use '%ctaid.x'. */ + bool GOMP_teams4 (unsigned int num_teams_lower, unsigned int num_teams_upper, unsigned int thread_limit, bool first) diff --git a/libgomp/target.c b/libgomp/target.c index e311e5a8302..47a18477b2a 100644 --- a/libgomp/target.c +++ b/libgomp/target.c @@ -4355,6 +4355,8 @@ gomp_target_task_fn (void *data) return false; } +/* Implement OpenMP 'teams' construct, legacy entry point. */ + void GOMP_teams (unsigned int num_teams, unsigned int thread_limit) { @@ -4367,6 +4369,13 @@ GOMP_teams (unsigned int num_teams, unsigned int thread_limit) (void) num_teams; } +/* Implement OpenMP 'teams' construct. + + Initialize upon FIRST call. Return whether this invocation is active. + Depending on whether NUM_TEAMS_LOW asks for more teams than are provided + in hardware, we may need to loop multiple times; in that case make sure to + update the team-level variable used by 'omp_get_team_num'. */ + bool GOMP_teams4 (unsigned int num_teams_low, unsigned int num_teams_high, unsigned int thread_limit, bool first) -- 2.34.1
