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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: "Marc Strämke" <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
Date: Tue, 17 Jun 2025 11:28:14 +0200	[thread overview]
Message-ID: <20250617092814.vqKdu23w@linutronix.de> (raw)
In-Reply-To: <97638b0b-cd96-40e2-9dc2-5e6f767b90a4@eltropuls.de>

On 2025-06-14 10:52:36 [+0200], Marc Strämke wrote:
>               ip-4931    [001] b...3   700.149995: igb_update_mc_addr_list <-igb_set_rx_mode
>               ip-4931    [001] Dn..3   700.150795: irq_disable: caller=irqentry_enter+0x2a/0x60 parent=0x0

Between those two functions you have 800us delay. Interrupts are not
disabled so the CPU stalls. As explained earlier, I expect the read on
the bus flushes the writes causing the spike.

Sebastian

  parent reply	other threads:[~2025-06-17  9:28 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-06-10 11:23 Latency spikes on V6.15.1 Preempt RT and maybe related to intel IGB Marc Strämke
2025-06-13 14:54 ` Sebastian Andrzej Siewior
     [not found]   ` <E1uQ6I0-000000003aa-37uJ@smtprelay05.ispgateway.de>
2025-06-13 19:58     ` Latency spikes on V6.15.1 Preempt RT and maybe related to intel? IGB Sebastian Andrzej Siewior
2025-06-14  8:52       ` Marc Strämke
2025-06-16 15:10         ` Marc Strämke
2025-06-17  9:16           ` Sebastian Andrzej Siewior
2025-06-17  9:08         ` Sebastian Andrzej Siewior
2025-06-17  9:28         ` Sebastian Andrzej Siewior [this message]
2025-06-17  9:45           ` Marc Strämke
2025-06-17 10:00             ` Sebastian Andrzej Siewior
2025-06-17 10:03               ` Marc Strämke
2025-06-17 10:15                 ` Sebastian Andrzej Siewior
2025-06-17 10:54                   ` Kurt Kanzenbach
     [not found]                     ` <19a46896-3d26-415b-9820-730a42b0702e@eltropuls.de>
2025-06-17 13:35                       ` Kurt Kanzenbach
     [not found]   ` <522704b0-5a35-42c3-9bcc-627b487b740c@eltropuls.de>
2025-06-14 18:13     ` Latency spikes on V6.15.1 Preempt RT and maybe related to intel IGB Sebastian Andrzej Siewior

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