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Message-ID: <761aa56f-55c4-e0d4-9f75-eef8035aa25b@ti.com>
Date: Mon, 1 Apr 2024 18:39:20 -0500
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Subject: Re: [PATCH 13/13] mailbox: omap: Remove kernel FIFO message queuing
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To: Andrew Davis <afd@ti.com>, Jassi Brar <jassisinghbrar@gmail.com>,
        Nick
 Saulnier <nsaulnier@ti.com>,
        Bjorn Andersson <andersson@kernel.org>,
        Mathieu
 Poirier <mathieu.poirier@linaro.org>
CC: <linux-remoteproc@vger.kernel.org>, <linux-kernel@vger.kernel.org>
References: <20240325172045.113047-1-afd@ti.com>
 <20240325172045.113047-14-afd@ti.com>
From: Hari Nagalla <hnagalla@ti.com>
In-Reply-To: <20240325172045.113047-14-afd@ti.com>
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On 3/25/24 12:20, Andrew Davis wrote:
> The kernel FIFO queue has a couple issues. The biggest issue is that
> it causes extra latency in a path that can be used in real-time tasks,
> such as communication with real-time remote processors.
> 
> The whole FIFO idea itself looks to be a leftover from before the
> unified mailbox framework. The current mailbox framework expects
> mbox_chan_received_data() to be called with data immediately as it
> arrives. Remove the FIFO and pass the messages to the mailbox
> framework directly.
Yes, this would definitely speed up the message receive path. With RT 
linux, the irq runs in thread context, so that is Ok. But with non-RT 
the whole receive path runs in interrupt context. So, i think it would 
be appropriate to use a threaded_irq()?