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Subject: Re: [PATCH v3 1/8] media: hantro: Trace hevc hw cycles performance
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From:   Ezequiel Garcia <ezequiel@collabora.com>
To:     Benjamin Gaignard <benjamin.gaignard@collabora.com>,
        hverkuil@xs4all.nl, p.zabel@pengutronix.de, mchehab@kernel.org,
        shawnguo@kernel.org, s.hauer@pengutronix.de, festevam@gmail.com,
        gregkh@linuxfoundation.org, mripard@kernel.org,
        paul.kocialkowski@bootlin.com, wens@csie.org,
        jernej.skrabec@siol.net, emil.l.velikov@gmail.com,
        andrzej.p@collabora.com, jc@kynesim.co.uk,
        jernej.skrabec@gmail.com, nicolas@ndufresne.ca
Cc:     kernel@pengutronix.de, linux-imx@nxp.com,
        linux-media@vger.kernel.org, linux-rockchip@lists.infradead.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Date:   Tue, 22 Jun 2021 09:48:49 -0300
In-Reply-To: <41682f40-3b5e-e21c-d75e-f57f8f3310da@collabora.com>
References: <20210618131526.566762-1-benjamin.gaignard@collabora.com>
         <20210618131526.566762-2-benjamin.gaignard@collabora.com>
         <418311dac48d3a29b4fe9e363f7d4e82c360f586.camel@collabora.com>
         <41682f40-3b5e-e21c-d75e-f57f8f3310da@collabora.com>
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On Tue, 2021-06-22 at 14:23 +0200, Benjamin Gaignard wrote:
[..]
> > > +
> > > +TRACE_EVENT(hantro_hevc_perf,
> > > +       TP_PROTO(struct hantro_ctx *ctx, u32 hw_cycles),
> > > +
> > > +       TP_ARGS(ctx, hw_cycles),
> > > +
> > > +       TP_STRUCT__entry(
> > > +               __field(int, minor)
> > > +               __field(u32, hw_cycles)
> > > +       ),
> > > +
> > > +       TP_fast_assign(
> > > +               __entry->minor = ctx->fh.vdev->minor;
> > Tracking performance per minor doesn't seem useful,
> > we'd like to track per-fd (i.e. per context).
> 
> This part of the driver doesn't know for which fd the decoding job is done
> so impossible to add it there.
> 

Maybe you can explore using struct v4l2_m2m_ctx.
There's an RFC where this is discussed:

https://lore.kernel.org/linux-media/20210517183801.1255496-1-emil.l.velikov@gmail.com/

Kindly,
Ezequiel