From: Vincent Guittot <vincent.guittot@linaro.org>
To: Linus Walleij <linus.walleij@linaro.org>
Cc: Allen Pais <apais@linux.microsoft.com>,
Arnd Bergmann <arnd@arndb.de>,
olivier.dautricourt@orolia.com, sr@denx.de, vkoul@kernel.org,
keescook@chromium.org, linux-hardening@vger.kernel.org,
ludovic.desroches@microchip.com, tudor.ambarus@microchip.com,
f.fainelli@gmail.com, rjui@broadcom.com, sbranden@broadcom.com,
bcm-kernel-feedback-list@broadcom.com, nsaenz@kernel.org,
paul@crapouillou.net, Eugeniy.Paltsev@synopsys.com,
gustavo.pimentel@synopsys.com, vireshk@kernel.org,
andriy.shevchenko@linux.intel.com, leoyang.li@nxp.com,
zw@zh-kernel.org, wangzhou1@hisilicon.com, shawnguo@kernel.org,
s.hauer@pengutronix.de, sean.wang@mediatek.com,
matthias.bgg@gmail.com, afaerber@suse.de, mani@kernel.org,
logang@deltatee.com, sanju.mehta@amd.com, daniel@zonque.org,
haojian.zhuang@gmail.com, robert.jarzmik@free.fr,
agross@kernel.org, bjorn.andersson@linaro.org,
krzysztof.kozlowski@linaro.org, green.wan@sifive.com,
orsonzhai@gmail.com, baolin.wang7@gmail.com,
zhang.lyra@gmail.com, patrice.chotard@foss.st.com, wens@csie.org,
jernej.skrabec@gmail.com, samuel@sholland.org,
dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC 1/1] drivers/dma/*: replace tasklets with workqueue
Date: Wed, 25 May 2022 11:52:53 +0200 [thread overview]
Message-ID: <CAKfTPtDzsxnsfR8dkyDwcaJvtGF4Ouo0SFj_PKd7W=AUq3jHZA@mail.gmail.com> (raw)
In-Reply-To: <CACRpkdZ2DFZRPHS1x0=M3_8zYvU-jpCG5Tm3863dXv51EhY+BA@mail.gmail.com>
On Wed, 25 May 2022 at 11:24, Linus Walleij <linus.walleij@linaro.org> wrote:
>
> On Tue, Apr 19, 2022 at 11:17 PM Allen Pais <apais@linux.microsoft.com> wrote:
>
> > The tasklet is an old API which will be deprecated, workqueue API
> > cab be used instead of them.
> >
> > This patch replaces the tasklet usage in drivers/dma/* with a
> > simple work.
> >
> > Github: https://github.com/KSPP/linux/issues/94
> >
> > Signed-off-by: Allen Pais <apais@linux.microsoft.com>
>
> Paging Vincent Guittot and Arnd Bergmann on the following question
> on this patch set:
>
> - Will replacing tasklets with workque like this negatively impact the
> performance on DMA engine bottom halves?
workqueue uses cfs thread so they will be scheduled like any other
thread. Furthermore, schedule_work uses the default system workqueue
which is shared with a lot of other stuff and doesn't parallel work so
you can expect some performance impact.
If you really want to use workqueue, you should at least create your
own workqueue. But you should also have a look at irq_work; An example
of usage is kernel/sched/sched_cpufrequtil.c
>
> For reference:
> https://lore.kernel.org/dmaengine/YoI4J8taHehMpjFj@matsya/
>
> Yours,
> Linus Walleij
next prev parent reply other threads:[~2022-05-25 9:53 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-19 21:16 [RFC 0/1] refactor all tasklet users into other APIs Allen Pais
2022-04-19 21:16 ` [RFC 1/1] drivers/dma/*: replace tasklets with workqueue Allen Pais
2022-04-20 2:31 ` Kees Cook
2022-04-22 16:48 ` Allen Pais
2022-04-25 15:06 ` Linus Walleij
2022-04-25 23:59 ` Allen Pais
2022-04-25 15:56 ` Krzysztof Kozlowski
2022-04-25 19:55 ` Gustavo A. R. Silva
2022-04-28 9:29 ` Andy Shevchenko
[not found] ` <DA101ED8-F99F-4DCB-9CB7-370A62C44B65@linux.microsoft.com>
2022-05-12 21:54 ` Linus Walleij
2022-05-16 11:40 ` Vinod Koul
2022-04-26 0:04 ` Allen Pais
2022-04-27 2:45 ` Vinod Koul
2022-04-27 15:20 ` Dave Jiang
2022-04-27 15:58 ` Allen Pais
2022-04-27 15:53 ` Allen Pais
2022-05-25 9:24 ` Linus Walleij
2022-05-25 9:52 ` Vincent Guittot [this message]
2022-05-25 11:03 ` Arnd Bergmann
2022-05-25 15:14 ` David Laight
[not found] ` <6E248F41-6687-4F2B-B847-DB5459BA1344@linux.microsoft.com>
2022-05-25 17:48 ` Arnd Bergmann
2022-05-25 18:04 ` Allen Pais
2022-05-27 8:06 ` Vinod Koul
2022-05-27 10:59 ` Arnd Bergmann
2022-05-31 6:56 ` Vinod Koul
[not found] ` <0A9EDEDC-9E6C-47F8-89C0-48DCDD3F9DE3@linux.microsoft.com>
2022-05-31 18:02 ` Arnd Bergmann
2022-05-31 18:19 ` Allen Pais
2022-05-31 19:27 ` Arnd Bergmann
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