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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: "marc.straemke" <marc.straemke@eltropuls.de>
Cc: linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org
Subject: Re: Latency spikes on V6.15.1 Preempt RT and maybe related to intel?
 IGB
Message-ID: <20250613195838.0-gZ6bqS@linutronix.de>
References: <20250613145434.T2x2ML8_@linutronix.de>
 <E1uQ6I0-000000003aa-37uJ@smtprelay05.ispgateway.de>
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In-Reply-To: <E1uQ6I0-000000003aa-37uJ@smtprelay05.ispgateway.de>

On 2025-06-13 17:26:15 [+0200], marc.straemke wrote:
> Thanks Sebastian, I will do that tomorrow.To confirm: Just pure event
> tracing without the function tracer? (After enabling the sched
> events)Regards,Marc=C2=A0

The event tracing should narrow down which of the tasks cause the spike.
So if you say it is the ip comment then you should see ip.
Step two would be the function tracer to narrow it down further. You
could start right away with the function tracer to see where the big gap
is.
rtla could speed up the whole process (via the timerlat auto analysis).

Sebastian