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From: Adrian Ratiu <adrian.ratiu@collabora•com>
To: git@vger•kernel.org, Jeff King <peff@peff•net>
Cc: Emily Shaffer <emilyshaffer@google•com>,
	Junio C Hamano <gitster@pobox•com>,
	Patrick Steinhardt <ps@pks•im>,
	Josh Steadmon <steadmon@google•com>,
	Kristoffer Haugsbakk <kristofferhaugsbakk@fastmail•com>,
	Adrian Ratiu <adrian.ratiu@collabora•com>
Subject: [PATCH v7 09/12] hook: add jobs option
Date: Wed, 21 Jan 2026 23:54:33 +0200	[thread overview]
Message-ID: <20260121215436.1473800-10-adrian.ratiu@collabora.com> (raw)
In-Reply-To: <20260121215436.1473800-1-adrian.ratiu@collabora.com>

Allow the API callers to specify the number of jobs across which
hook execution can be parallelized. It defaults to 1 and no hook
currently changes it, so all hooks run sequentially as before.

This allows us to both pave the way for parallel hook execution
(that will be a follow-up patch series building upon this) and to
finish the API conversion of builtin/receive-pack.c, keeping the
output muxer thread design as Peff suggested.

When .jobs == 1 nothing changes, the simple "copy_to_sideband" mux
still outputs directly via sideband channel 2, keeping the current
(mostly) real-time output characteristics, avoids unecessary poll
delays or deadlock risks.

When .jobs > 1, a more complex muxer is needed, to buffer the hook
output and avoid interleaving. After working on this mux I quickly
realized I was re-implementing run-command with ungroup=0 so that
ideas was dropped in favor of run-command which outputs to stderr.
Then run-command's stderr just connects to the simple muxer input.

Maybe it's better to understand using ascii graphics:

 [ Sequential (jobs = 1) ]             [ Parallel (jobs > 1) ]

 +--------------+                      +--------+   +--------+
 | Hook Process |                      | Hook 1 |   | Hook 2 |
 +--------------+                      +--------+   +--------+
        |                                  |             |
        | stderr (inherited)               | stderr pipe |
        |                                  | (captured)  |
        v                                  v             v
 +-------------------------------------------------------------+
 |                      Parent Process                         |
 |                                                             |
 |      (direct write)              [run-command (buffered)]   |
 |             |                                 |             |
 |             |                                 | writes      |
 |             v                                 v             |
 |      +-------------------------------------------+          |
 |      |             stderr (FD 2)                 |          |
 |      +-------------------------------------------+          |
 |                           |                                 |
 |                           | (dup2'd to pipe)                |
 |                           v                                 |
 |               +-------------------------+                   |
 |               | sideband "muxer" thread |                   |
 |               +-------------------------+                   |
 +-------------------------------------------------------------+

When use_sideband == 0, the sideband muxer thread is missing, so
the same architecture just outputs via the parent stderr stream.

See the following commits for the hook API conversions doing this,
using pre-existing sideband thread logic from `copy_to_sideband`.

Suggested-by: Jeff King <peff@peff•net>
Signed-off-by: Adrian Ratiu <adrian.ratiu@collabora•com>
---
 hook.c | 7 +++++--
 hook.h | 9 +++++++++
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/hook.c b/hook.c
index fde1f88ce8..aafed134af 100644
--- a/hook.c
+++ b/hook.c
@@ -152,8 +152,8 @@ int run_hooks_opt(struct repository *r, const char *hook_name,
 		.tr2_category = "hook",
 		.tr2_label = hook_name,
 
-		.processes = 1,
-		.ungroup = 1,
+		.processes = options->jobs,
+		.ungroup = options->jobs <= 1,
 
 		.get_next_task = pick_next_hook,
 		.start_failure = notify_start_failure,
@@ -169,6 +169,9 @@ int run_hooks_opt(struct repository *r, const char *hook_name,
 	if (options->path_to_stdin && options->feed_pipe)
 		BUG("options path_to_stdin and feed_pipe are mutually exclusive");
 
+	if (!options->jobs)
+		BUG("run_hooks_opt must be called with options.jobs >= 1");
+
 	if (options->invoked_hook)
 		*options->invoked_hook = 0;
 
diff --git a/hook.h b/hook.h
index 7cbeef0a1e..3db860bf3c 100644
--- a/hook.h
+++ b/hook.h
@@ -16,6 +16,14 @@ struct run_hooks_opt
 	/* Emit an error if the hook is missing */
 	unsigned int error_if_missing:1;
 
+	/**
+	 *  Number of processes to parallelize across.
+	 *
+	 * If > 1, output will be buffered and de-interleaved (ungroup=0).
+	 * If == 1, output will be real-time (ungroup=1).
+	 */
+	unsigned int jobs;
+
 	/**
 	 * An optional initial working directory for the hook,
 	 * translates to "struct child_process"'s "dir" member.
@@ -86,6 +94,7 @@ struct run_hooks_opt
 	.env = STRVEC_INIT, \
 	.args = STRVEC_INIT, \
 	.stdout_to_stderr = 1, \
+	.jobs = 1, \
 }
 
 struct hook_cb_data {
-- 
2.52.0.732.gb351b5166d.dirty


  parent reply	other threads:[~2026-01-21 21:55 UTC|newest]

Thread overview: 187+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-09-25 12:53 [PATCH 00/10] Convert remaining hooks to hook.h Adrian Ratiu
2025-09-25 12:53 ` [PATCH 01/10] run-command: add stdin callback for parallelization Adrian Ratiu
2025-10-02  6:34   ` Patrick Steinhardt
2025-10-02 15:46     ` Junio C Hamano
2025-10-06 13:01       ` Adrian Ratiu
2025-10-06 12:59     ` Adrian Ratiu
2025-10-14 17:35       ` Adrian Ratiu
2025-09-25 12:53 ` [PATCH 02/10] hook: provide stdin via callback Adrian Ratiu
2025-09-25 20:05   ` Junio C Hamano
2025-09-26 12:03     ` Adrian Ratiu
2025-10-10 19:57   ` Emily Shaffer
2025-10-13 14:47     ` Adrian Ratiu
2025-09-25 12:53 ` [PATCH 03/10] hook: convert 'post-rewrite' hook in sequencer.c to hook.h Adrian Ratiu
2025-09-25 20:15   ` Junio C Hamano
2025-09-26 12:29     ` Adrian Ratiu
2025-09-26 14:12   ` Phillip Wood
2025-09-26 15:53     ` Adrian Ratiu
2025-09-29 10:11       ` Phillip Wood
2025-09-26 17:52     ` Junio C Hamano
2025-09-29  7:33       ` Adrian Ratiu
2025-10-02  6:34   ` Patrick Steinhardt
2025-10-08  7:04     ` Adrian Ratiu
2025-09-25 12:53 ` [PATCH 04/10] transport: convert pre-push hook " Adrian Ratiu
2025-09-25 18:58   ` D. Ben Knoble
2025-09-26 13:02     ` Adrian Ratiu
2025-09-26 14:11   ` Phillip Wood
2025-09-29 11:33     ` Adrian Ratiu
2025-09-25 12:53 ` [PATCH 05/10] reference-transaction: use hook.h to run hooks Adrian Ratiu
2025-09-25 21:45   ` Junio C Hamano
2025-09-26 13:03     ` Adrian Ratiu
2025-10-02  6:34   ` Patrick Steinhardt
2025-10-08 12:26     ` Adrian Ratiu
2025-09-25 12:53 ` [PATCH 06/10] run-command: allow capturing of collated output Adrian Ratiu
2025-09-25 21:52   ` Junio C Hamano
2025-09-26 14:14     ` Adrian Ratiu
2025-09-25 12:53 ` [PATCH 07/10] hooks: allow callers to capture output Adrian Ratiu
2025-09-25 12:53 ` [PATCH 08/10] receive-pack: convert 'update' hook to hook.h Adrian Ratiu
2025-09-25 21:53   ` Junio C Hamano
2025-10-10 19:57   ` Emily Shaffer
2025-10-17  8:27     ` Adrian Ratiu
2025-09-25 12:53 ` [PATCH 09/10] post-update: use hook.h library Adrian Ratiu
2025-09-25 18:02 ` [PATCH 10/10] receive-pack: convert receive hooks to hook.h Adrian Ratiu
2025-10-10 19:57 ` [PATCH 00/10] Convert remaining " Emily Shaffer
2025-10-17 14:15 ` [PATCH v2 " Adrian Ratiu
2025-10-17 14:15   ` [PATCH v2 01/10] run-command: add stdin callback for parallelization Adrian Ratiu
2025-10-21  7:40     ` Patrick Steinhardt
2025-10-17 14:15   ` [PATCH v2 02/10] hook: provide stdin via callback Adrian Ratiu
2025-10-21  7:41     ` Patrick Steinhardt
2025-10-21  7:41     ` Patrick Steinhardt
2025-10-21 14:44       ` Adrian Ratiu
2025-10-17 14:15   ` [PATCH v2 03/10] hook: convert 'post-rewrite' hook in sequencer.c to hook API Adrian Ratiu
2025-10-21  7:41     ` Patrick Steinhardt
2025-10-21 15:44       ` Adrian Ratiu
2025-10-17 14:15   ` [PATCH v2 04/10] transport: convert pre-push " Adrian Ratiu
2025-10-21  7:41     ` Patrick Steinhardt
2025-10-21 16:04       ` Adrian Ratiu
2025-10-17 14:15   ` [PATCH v2 05/10] reference-transaction: use hook API instead of run-command Adrian Ratiu
2025-10-17 14:15   ` [PATCH v2 06/10] hook: allow overriding the ungroup option Adrian Ratiu
2025-10-17 14:15   ` [PATCH v2 07/10] run-command: allow capturing of collated output Adrian Ratiu
2025-10-21  7:41     ` Patrick Steinhardt
2025-10-21 16:25       ` Adrian Ratiu
2025-10-17 14:15   ` [PATCH v2 08/10] hooks: allow callers to capture output Adrian Ratiu
2025-10-17 14:15   ` [PATCH v2 09/10] receive-pack: convert update hooks to new API Adrian Ratiu
2025-10-28 18:39     ` Kristoffer Haugsbakk
2025-10-17 14:15   ` [PATCH v2 10/10] receive-pack: convert receive hooks to hook API Adrian Ratiu
2025-10-21  7:41     ` Patrick Steinhardt
2025-10-28 18:42     ` Kristoffer Haugsbakk
2025-10-29 13:46       ` Adrian Ratiu
2025-10-29 13:50         ` Kristoffer Haugsbakk
2025-11-15 19:48     ` Junio C Hamano
2025-11-17 16:51       ` Adrian Ratiu
2025-10-21  7:40   ` [PATCH v2 00/10] Convert remaining hooks to hook.h Patrick Steinhardt
2025-10-21 16:34     ` Adrian Ratiu
2025-11-24 17:20 ` [PATCH v3 " Adrian Ratiu
2025-11-24 17:20   ` [PATCH v3 01/10] run-command: add stdin callback for parallelization Adrian Ratiu
2025-11-25 23:15     ` Junio C Hamano
2025-11-27 12:00       ` Adrian Ratiu
2025-11-24 17:20   ` [PATCH v3 02/10] hook: provide stdin via callback Adrian Ratiu
2025-11-29 13:03     ` Adrian Ratiu
2025-11-29 22:21       ` Junio C Hamano
2025-12-01 13:26         ` Adrian Ratiu
2025-11-24 17:20   ` [PATCH v3 03/10] hook: convert 'post-rewrite' hook in sequencer.c to hook API Adrian Ratiu
2025-11-24 17:20   ` [PATCH v3 04/10] transport: convert pre-push " Adrian Ratiu
2025-11-24 22:55     ` Junio C Hamano
2025-11-27 14:24       ` Adrian Ratiu
2025-11-24 17:20   ` [PATCH v3 05/10] reference-transaction: use hook API instead of run-command Adrian Ratiu
2025-11-24 17:20   ` [PATCH v3 06/10] hook: allow overriding the ungroup option Adrian Ratiu
2025-11-24 17:20   ` [PATCH v3 07/10] run-command: allow capturing of collated output Adrian Ratiu
2025-11-24 17:20   ` [PATCH v3 08/10] hooks: allow callers to capture output Adrian Ratiu
2025-11-24 17:20   ` [PATCH v3 09/10] receive-pack: convert update hooks to new API Adrian Ratiu
2025-11-24 17:20   ` [PATCH v3 10/10] receive-pack: convert receive hooks to hook API Adrian Ratiu
2025-12-04 14:15 ` [PATCH v4 00/11] Convert remaining hooks to hook.h Adrian Ratiu
2025-12-04 14:15   ` [PATCH v4 01/11] run-command: add first helper for pp child states Adrian Ratiu
2025-12-04 14:15   ` [PATCH v4 02/11] run-command: add stdin callback for parallelization Adrian Ratiu
2025-12-04 14:15   ` [PATCH v4 03/11] hook: provide stdin via callback Adrian Ratiu
2025-12-16  8:08     ` Patrick Steinhardt
2025-12-04 14:15   ` [PATCH v4 04/11] hook: convert 'post-rewrite' hook in sequencer.c to hook API Adrian Ratiu
2025-12-04 14:15   ` [PATCH v4 05/11] transport: convert pre-push " Adrian Ratiu
2025-12-16  8:08     ` Patrick Steinhardt
2025-12-16  9:09       ` Adrian Ratiu
2025-12-16  9:30         ` Patrick Steinhardt
2025-12-17 23:07           ` Junio C Hamano
2025-12-04 14:15   ` [PATCH v4 06/11] reference-transaction: use hook API instead of run-command Adrian Ratiu
2025-12-04 14:15   ` [PATCH v4 07/11] hook: allow overriding the ungroup option Adrian Ratiu
2025-12-04 14:15   ` [PATCH v4 08/11] run-command: allow capturing of collated output Adrian Ratiu
2025-12-04 14:15   ` [PATCH v4 09/11] hooks: allow callers to capture output Adrian Ratiu
2025-12-04 14:15   ` [PATCH v4 10/11] receive-pack: convert update hooks to new API Adrian Ratiu
2025-12-16  8:08     ` Patrick Steinhardt
2025-12-16  9:22       ` Adrian Ratiu
2025-12-04 14:15   ` [PATCH v4 11/11] receive-pack: convert receive hooks to hook API Adrian Ratiu
2025-12-18 17:11 ` [PATCH v5 00/11] Convert remaining hooks to hook.h Adrian Ratiu
2025-12-18 17:11   ` [PATCH v5 01/11] run-command: add first helper for pp child states Adrian Ratiu
2025-12-18 17:11   ` [PATCH v5 02/11] run-command: add stdin callback for parallelization Adrian Ratiu
2025-12-18 17:11   ` [PATCH v5 03/11] hook: provide stdin via callback Adrian Ratiu
2025-12-18 17:11   ` [PATCH v5 04/11] hook: convert 'post-rewrite' hook in sequencer.c to hook API Adrian Ratiu
2025-12-18 17:11   ` [PATCH v5 05/11] transport: convert pre-push " Adrian Ratiu
2025-12-18 17:11   ` [PATCH v5 06/11] reference-transaction: use hook API instead of run-command Adrian Ratiu
2025-12-18 17:11   ` [PATCH v5 07/11] hook: allow overriding the ungroup option Adrian Ratiu
2025-12-18 17:11   ` [PATCH v5 08/11] run-command: allow capturing of collated output Adrian Ratiu
2025-12-18 17:11   ` [PATCH v5 09/11] hooks: allow callers to capture output Adrian Ratiu
2025-12-18 17:11   ` [PATCH v5 10/11] receive-pack: convert update hooks to new API Adrian Ratiu
2025-12-18 17:11   ` [PATCH v5 11/11] receive-pack: convert receive hooks to hook API Adrian Ratiu
2025-12-19 12:38     ` Patrick Steinhardt
2025-12-20 10:40       ` Adrian Ratiu
2025-12-26 12:23 ` [PATCH v6 00/11] Convert remaining hooks to hook.h Adrian Ratiu
2025-12-26 12:23   ` [PATCH v6 01/11] run-command: add first helper for pp child states Adrian Ratiu
2025-12-26 12:23   ` [PATCH v6 02/11] run-command: add stdin callback for parallelization Adrian Ratiu
2025-12-26 12:23   ` [PATCH v6 03/11] hook: provide stdin via callback Adrian Ratiu
2025-12-26 12:23   ` [PATCH v6 04/11] hook: convert 'post-rewrite' hook in sequencer.c to hook API Adrian Ratiu
2025-12-26 12:23   ` [PATCH v6 05/11] transport: convert pre-push " Adrian Ratiu
2025-12-26 12:23   ` [PATCH v6 06/11] reference-transaction: use hook API instead of run-command Adrian Ratiu
2026-01-18 12:23     ` SZEDER Gábor
2026-01-18 18:30       ` Adrian Ratiu
2025-12-26 12:23   ` [PATCH v6 07/11] hook: allow overriding the ungroup option Adrian Ratiu
2025-12-26 12:23   ` [PATCH v6 08/11] run-command: allow capturing of collated output Adrian Ratiu
2025-12-26 12:23   ` [PATCH v6 09/11] hooks: allow callers to capture output Adrian Ratiu
2025-12-26 12:23   ` [PATCH v6 10/11] receive-pack: convert update hooks to new API Adrian Ratiu
2025-12-26 12:23   ` [PATCH v6 11/11] receive-pack: convert receive hooks to hook API Adrian Ratiu
2025-12-28 11:32   ` [PATCH v6 00/11] Convert remaining hooks to hook.h Junio C Hamano
2026-01-05 10:52     ` Adrian Ratiu
2026-01-05 12:13       ` Patrick Steinhardt
2026-01-21 21:54 ` [PATCH v7 00/12] " Adrian Ratiu
2026-01-21 21:54   ` [PATCH v7 01/12] t1800: add hook output stream tests Adrian Ratiu
2026-01-21 22:16     ` Junio C Hamano
2026-01-22  9:19       ` Adrian Ratiu
2026-01-21 21:54   ` [PATCH v7 02/12] run-command: add first helper for pp child states Adrian Ratiu
2026-01-21 23:01     ` Junio C Hamano
2026-01-22  9:21       ` Adrian Ratiu
2026-01-21 21:54   ` [PATCH v7 03/12] run-command: add stdin callback for parallelization Adrian Ratiu
2026-01-21 21:54   ` [PATCH v7 04/12] hook: provide stdin via callback Adrian Ratiu
2026-01-21 21:54   ` [PATCH v7 05/12] hook: convert 'post-rewrite' hook in sequencer.c to hook API Adrian Ratiu
2026-01-21 21:54   ` [PATCH v7 06/12] hook: allow separate std[out|err] streams Adrian Ratiu
2026-01-23  7:19     ` Patrick Steinhardt
2026-01-23  7:47       ` Adrian Ratiu
2026-01-21 21:54   ` [PATCH v7 07/12] transport: convert pre-push to hook API Adrian Ratiu
2026-01-21 21:54   ` [PATCH v7 08/12] reference-transaction: use hook API instead of run-command Adrian Ratiu
2026-01-21 21:54   ` Adrian Ratiu [this message]
2026-01-21 21:54   ` [PATCH v7 10/12] run-command: poll child stdin in addition to stdout Adrian Ratiu
2026-01-21 22:04     ` Kristoffer Haugsbakk
2026-01-22  9:57       ` Adrian Ratiu
2026-01-21 23:11     ` Junio C Hamano
2026-01-22 10:58       ` Adrian Ratiu
2026-01-22 17:20         ` Junio C Hamano
2026-01-26 23:20     ` Emily Shaffer
2026-01-27  0:11       ` Junio C Hamano
2026-01-27 10:10         ` Adrian Ratiu
2026-01-21 21:54   ` [PATCH v7 11/12] receive-pack: convert update hooks to new API Adrian Ratiu
2026-01-21 22:14     ` Kristoffer Haugsbakk
2026-01-22  9:26       ` Adrian Ratiu
2026-01-27  0:12     ` Emily Shaffer
2026-01-27 13:05       ` Adrian Ratiu
2026-01-21 21:54   ` [PATCH v7 12/12] receive-pack: convert receive hooks to hook API Adrian Ratiu
2026-01-28 21:39 ` [PATCH v8 00/12] Convert remaining hooks to hook.h Adrian Ratiu
2026-01-28 21:39   ` [PATCH v8 01/12] t1800: add hook output stream tests Adrian Ratiu
2026-01-28 21:39   ` [PATCH v8 02/12] run-command: add helper for pp child states Adrian Ratiu
2026-01-28 21:39   ` [PATCH v8 03/12] run-command: add stdin callback for parallelization Adrian Ratiu
2026-01-28 21:39   ` [PATCH v8 04/12] hook: provide stdin via callback Adrian Ratiu
2026-01-28 21:39   ` [PATCH v8 05/12] hook: convert 'post-rewrite' hook in sequencer.c to hook API Adrian Ratiu
2026-01-28 21:39   ` [PATCH v8 06/12] hook: allow separate std[out|err] streams Adrian Ratiu
2026-02-02  3:17     ` Chris Darroch
2026-02-02 16:32       ` Junio C Hamano
2026-01-28 21:39   ` [PATCH v8 07/12] transport: convert pre-push to hook API Adrian Ratiu
2026-01-28 21:39   ` [PATCH v8 08/12] reference-transaction: use hook API instead of run-command Adrian Ratiu
2026-01-28 21:39   ` [PATCH v8 09/12] hook: add jobs option Adrian Ratiu
2026-01-28 21:39   ` [PATCH v8 10/12] run-command: poll child input in addition to output Adrian Ratiu
2026-01-28 21:39   ` [PATCH v8 11/12] receive-pack: convert update hooks to new API Adrian Ratiu
2026-01-28 21:39   ` [PATCH v8 12/12] receive-pack: convert receive hooks to hook API Adrian Ratiu

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