From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: Herve Codina <herve.codina@bootlin.com>,
Qiang Zhao <qiang.zhao@nxp.com>,
Shengjiu Wang <shengjiu.wang@gmail.com>,
Xiubo Li <Xiubo.Lee@gmail.com>,
Fabio Estevam <festevam@gmail.com>,
Nicolin Chen <nicoleotsuka@gmail.com>,
Liam Girdwood <lgirdwood@gmail.com>,
Mark Brown <broonie@kernel.org>, Jaroslav Kysela <perex@perex.cz>,
Takashi Iwai <tiwai@suse.com>
Cc: linuxppc-dev@lists.ozlabs.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-sound@vger.kernel.org
Subject: Re: [PATCH RESEND v3 0/4] ASoC: fsl: fsl_qmc_audio: Reduce amount of interrupts
Date: Thu, 18 Sep 2025 18:37:45 +0200 [thread overview]
Message-ID: <bad14e16-0d1c-411a-8b3d-89d8df05b9b5@csgroup.eu> (raw)
In-Reply-To: <cover.1758209158.git.christophe.leroy@csgroup.eu>
Le 18/09/2025 à 17:34, Christophe Leroy a écrit :
> This is a RESEND of v3 sent one month ago, see:
> https://lore.kernel.org/all/cover.1754993232.git.christophe.leroy@csgroup.eu/
Sorry for the noise, v3 was
https://lore.kernel.org/all/cover.1755504428.git.christophe.leroy@csgroup.eu/
The resent is correct though, only this reference in the cover is wrong.
Christophe
>
> This series reduces significantly the amount of interrupts on
> fsl_qmc_audio device.
>
> Patches 1 and 2 are preparatory patches.
> Patch 3 is the main change
> Patch 4 is a cleanup which is enabled by previous patch
>
> Changes in v3:
> - Properly check the buffer descriptor is unused (Patch 1, comment from Herve Codina)
> - Fixed copy/paste error (patch 2, comment from Herve Codina)
> - Fixed build failure (patch 2, comment from Herve Codina and Test robot)
>
> Changes in v2:
> - Don't remove UB bit (Patch 1, comment from Herve Codina)
> - Make sure audio channels are ordered on TDM bus (Patch 2, new patch, comment from Herve Codina)
> - Drop struct qmc_dai_chan (patch 4, new patch)
>
> Backgroup (copied from patch 3):
>
> In non-interleaved mode, several QMC channels are used in sync.
> More details can be found in commit 188d9cae5438 ("ASoC: fsl:
> fsl_qmc_audio: Add support for non-interleaved mode.")
> At the time being, an interrupt is requested on each channel to
> perform capture/playback completion, allthough the completion is
> really performed only once all channels have completed their work.
>
> This leads to a lot more interrupts than really needed. Looking at
> /proc/interrupts shows ~3800 interrupts per second when using
> 4 capture and 4 playback devices with 5ms periods while
> only 1600 (200 x 4 + 200 x 4) periods are processed during one second.
>
> The QMC channels work in sync, the one started first is the one
> finishing first and the one started last is the one finishing last,
> so when the last one finishes it is guaranteed that the other ones are
> finished as well. Therefore only request completion processing on the
> last QMC channel.
>
> On my board with the above exemple, on a kernel started with
> 'threadirqs' option, the QMC irq thread uses 16% CPU time with this
> patch while it uses 26% CPU time without this patch.
>
> Christophe Leroy (4):
> soc: fsl: qmc: Only set completion interrupt when needed
> ASoc: fsl: fsl_qmc_audio: Ensure audio channels are ordered in TDM bus
> ASoC: fsl: fsl_qmc_audio: Only request completion on last channel
> ASoc: fsl: fsl_qmc_audio: Drop struct qmc_dai_chan
>
> drivers/soc/fsl/qe/qmc.c | 44 +++++++++---
> sound/soc/fsl/fsl_qmc_audio.c | 125 +++++++++++++++-------------------
> 2 files changed, 87 insertions(+), 82 deletions(-)
>
next prev parent reply other threads:[~2025-09-18 18:20 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-18 15:34 [PATCH RESEND v3 0/4] ASoC: fsl: fsl_qmc_audio: Reduce amount of interrupts Christophe Leroy
2025-09-18 15:34 ` [PATCH RESEND v3 1/4] soc: fsl: qmc: Only set completion interrupt when needed Christophe Leroy
2025-09-18 15:34 ` [PATCH RESEND v3 2/4] ASoc: fsl: fsl_qmc_audio: Ensure audio channels are ordered in TDM bus Christophe Leroy
2025-09-18 15:34 ` [PATCH RESEND v3 3/4] ASoC: fsl: fsl_qmc_audio: Only request completion on last channel Christophe Leroy
2025-09-18 15:34 ` [PATCH RESEND v3 4/4] ASoc: fsl: fsl_qmc_audio: Drop struct qmc_dai_chan Christophe Leroy
2025-09-18 16:37 ` Christophe Leroy [this message]
2025-09-18 20:19 ` [PATCH RESEND v3 0/4] ASoC: fsl: fsl_qmc_audio: Reduce amount of interrupts Mark Brown
2025-09-19 21:06 ` Mark Brown
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