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Date: Fri, 15 Nov 2024 10:25:54 -0500
From: Steven Rostedt <rostedt@goodmis.org>
To: Jean-Michel Hautbois <jeanmichel.hautbois@yoseli.org>
Cc: linux-m68k@lists.linux-m68k.org, linux-kernel@vger.kernel.org,
 linux-trace-kernel@vger.kernel.org, Geert Uytterhoeven
 <geert@linux-m68k.org>, Greg Ungerer <gerg@linux-m68k.org>
Subject: Re: [PATCH RFC 0/2] Add basic tracing support for m68k
Message-ID: <20241115102554.29232d34@gandalf.local.home>
In-Reply-To: <3a8f6faa-62c6-4d32-b544-3fb7c00730d7@yoseli.org>
References: <20241021-add-m68k-tracing-support-v1-0-0883d704525b@yoseli.org>
	<3a8f6faa-62c6-4d32-b544-3fb7c00730d7@yoseli.org>
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On Fri, 15 Nov 2024 09:26:07 +0100
Jean-Michel Hautbois <jeanmichel.hautbois@yoseli.org> wrote:

> Nevertheless it sounds like a really high latency for wake_up().
> 
> I have a custom driver which basically gets an IRQ, and calls wake_up on 
> a read() call. This wake_up() on a high cpu usage can be more than 1ms ! 
> Even with a fifo/99 priority for my kernel thread !
> 
> I don't know if it rings any bell ?
> I can obviously do more tests if it can help getting down to the issue :-).

Try running timerlat.

-- Steve