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From: Namhyung Kim <namhyung@kernel.org>
To: Riccardo Mancini <rickyman7@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>,
	Ian Rogers <irogers@google.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Mark Rutland <mark.rutland@arm.com>, Jiri Olsa <jolsa@redhat.com>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	linux-perf-users <linux-perf-users@vger.kernel.org>,
	Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com>
Subject: Re: [RFC PATCH v3 08/15] perf workqueue: add queue_work and flush_workqueue functions
Date: Tue, 24 Aug 2021 12:40:40 -0700	[thread overview]
Message-ID: <CAM9d7ch4RM5rKrYLKrny3yt3ciK87aqzJ8Wt3ze87u9KBHjyXg@mail.gmail.com> (raw)
In-Reply-To: <f9100c6e428eafe1b9761f947550e45ccc9e8849.1629454773.git.rickyman7@gmail.com>

On Fri, Aug 20, 2021 at 3:54 AM Riccardo Mancini <rickyman7@gmail.com> wrote:
>
> This patch adds functions to queue and wait work_structs, and
> related tests.
>
> When a new work item is added, the workqueue first checks if there
> are threads to wake up. If so, it wakes it up with the given work item,
> otherwise it will pick the next round-robin thread and queue the work
> item to its queue. A thread which completes its queue will go to sleep.
>
> The round-robin mechanism is implemented through the next_worker
> attibute which will point to the next worker to be chosen for queueing.
> When work is assigned to that worker or when the worker goes to sleep,
> the pointer is moved to the next worker in the busy_list, if any.
> When a worker is woken up, it is added in the busy list just before the
> next_worker, so that it will be chosen as last (it's just been assigned
> a work item).

Do we really need this?  I think some of the complexity comes
because of this.  Can we simply put the works in a list in wq
and workers take it out with a lock?  Then the kernel will
distribute the works among the threads for us.

Maybe we can get rid of worker->lock too..

Thanks,
Namhyung

  reply	other threads:[~2021-08-24 19:40 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-20 10:53 [RFC PATCH v3 00/15] perf: add workqueue library and use it in synthetic-events Riccardo Mancini
2021-08-20 10:53 ` [RFC PATCH v3 01/15] perf workqueue: threadpool creation and destruction Riccardo Mancini
2021-08-20 10:53 ` [RFC PATCH v3 02/15] perf tests: add test for workqueue Riccardo Mancini
2021-08-20 10:53 ` [RFC PATCH v3 03/15] perf workqueue: add threadpool start and stop functions Riccardo Mancini
2021-08-20 10:53 ` [RFC PATCH v3 04/15] perf workqueue: add threadpool execute and wait functions Riccardo Mancini
2021-08-20 10:53 ` [RFC PATCH v3 05/15] tools: add sparse context/locking annotations in compiler-types.h Riccardo Mancini
2021-08-20 10:53 ` [RFC PATCH v3 06/15] perf workqueue: introduce workqueue struct Riccardo Mancini
2021-08-24 19:27   ` Namhyung Kim
2021-08-31 16:13     ` Riccardo Mancini
2021-08-20 10:53 ` [RFC PATCH v3 07/15] perf workqueue: implement worker thread and management Riccardo Mancini
2021-08-30  7:22   ` Jiri Olsa
2021-08-20 10:53 ` [RFC PATCH v3 08/15] perf workqueue: add queue_work and flush_workqueue functions Riccardo Mancini
2021-08-24 19:40   ` Namhyung Kim [this message]
2021-08-31 16:23     ` Riccardo Mancini
2021-08-20 10:53 ` [RFC PATCH v3 09/15] perf workqueue: spinup threads when needed Riccardo Mancini
2021-08-20 10:53 ` [RFC PATCH v3 10/15] perf workqueue: create global workqueue Riccardo Mancini
2021-08-20 10:53 ` [RFC PATCH v3 11/15] perf workqueue: add utility to execute a for loop in parallel Riccardo Mancini
2021-08-20 10:53 ` [RFC PATCH v3 12/15] perf record: setup global workqueue Riccardo Mancini
2021-08-20 10:53 ` [RFC PATCH v3 13/15] perf top: " Riccardo Mancini
2021-08-20 10:54 ` [RFC PATCH v3 14/15] perf test/synthesis: " Riccardo Mancini
2021-08-20 10:54 ` [RFC PATCH v3 15/15] perf synthetic-events: use workqueue parallel_for Riccardo Mancini
2021-08-29 21:59 ` [RFC PATCH v3 00/15] perf: add workqueue library and use it in synthetic-events Jiri Olsa
2021-08-31 15:46   ` Jiri Olsa
2021-08-31 16:57     ` Riccardo Mancini

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