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From: John Ogness <john.ogness@linutronix.de>
To: Peter Geis <pgwipeout@gmail.com>
Cc: Petr Mladek <pmladek@suse.com>,
	Sergey Senozhatsky <senozhatsky@chromium.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	"open list:ARM/Rockchip SoC..."
	<linux-rockchip@lists.infradead.org>
Subject: Re: [BUG] Threaded printk breaks early debugging
Date: Mon, 13 Jun 2022 01:14:50 +0206	[thread overview]
Message-ID: <87zgihlbst.fsf@jogness.linutronix.de> (raw)
In-Reply-To: <CAMdYzYr-Wo713Y4qjboTpoK6GcrYfKCfRJAEizwXw6-=dymVzg@mail.gmail.com>

On 2022-06-10, Peter Geis <pgwipeout@gmail.com> wrote:
> This might be a side effect of the fact that this is on a low powered
> arm64 board. I noticed with threading enabled during large bursts the
> console drops an excessive amount of messages. It's especially
> apparent during the handover from earlycon to the normal console.

I guess you have a very small kernel buffer and are generating unusually
high amounts of messages? Is there a reason you cannot use a larger
buffer?

Or maybe you are generating a constant amount of messages that a serial
port could never keep up with unless it was interfering with the system
in such a way as to slow everything down? This is exactly what printk
should _not_ be used for.

John Ogness

_______________________________________________
Linux-rockchip mailing list
Linux-rockchip@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-rockchip

WARNING: multiple messages have this Message-ID (diff)
From: John Ogness <john.ogness@linutronix.de>
To: Peter Geis <pgwipeout@gmail.com>
Cc: Petr Mladek <pmladek@suse.com>,
	Sergey Senozhatsky <senozhatsky@chromium.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	"open list:ARM/Rockchip SoC..."
	<linux-rockchip@lists.infradead.org>
Subject: Re: [BUG] Threaded printk breaks early debugging
Date: Mon, 13 Jun 2022 01:14:50 +0206	[thread overview]
Message-ID: <87zgihlbst.fsf@jogness.linutronix.de> (raw)
In-Reply-To: <CAMdYzYr-Wo713Y4qjboTpoK6GcrYfKCfRJAEizwXw6-=dymVzg@mail.gmail.com>

On 2022-06-10, Peter Geis <pgwipeout@gmail.com> wrote:
> This might be a side effect of the fact that this is on a low powered
> arm64 board. I noticed with threading enabled during large bursts the
> console drops an excessive amount of messages. It's especially
> apparent during the handover from earlycon to the normal console.

I guess you have a very small kernel buffer and are generating unusually
high amounts of messages? Is there a reason you cannot use a larger
buffer?

Or maybe you are generating a constant amount of messages that a serial
port could never keep up with unless it was interfering with the system
in such a way as to slow everything down? This is exactly what printk
should _not_ be used for.

John Ogness

  parent reply	other threads:[~2022-06-12 23:09 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-10 12:48 [BUG] Threaded printk breaks early debugging Peter Geis
2022-06-10 12:48 ` Peter Geis
2022-06-10 15:05 ` John Ogness
2022-06-10 15:05   ` John Ogness
2022-06-10 15:34   ` Peter Geis
2022-06-10 15:34     ` Peter Geis
2022-06-12  2:57     ` Sergey Senozhatsky
2022-06-12  2:57       ` Sergey Senozhatsky
2022-06-12 13:30       ` Peter Geis
2022-06-12 13:30         ` Peter Geis
2022-06-12 23:08     ` John Ogness [this message]
2022-06-12 23:08       ` John Ogness
2022-06-12 23:30       ` Peter Geis
2022-06-12 23:30         ` Peter Geis
2022-06-13  2:23         ` John Ogness
2022-06-13  2:23           ` John Ogness
2022-06-13 15:11           ` Petr Mladek
2022-06-13 15:11             ` Petr Mladek
2022-06-13 22:20             ` Peter Geis
2022-06-13 22:20               ` Peter Geis
2022-06-14  8:38               ` Petr Mladek
2022-06-14  8:38                 ` Petr Mladek
2022-06-13 11:24         ` Petr Mladek
2022-06-13 11:24           ` Petr Mladek
2022-06-12  3:13   ` Sergey Senozhatsky
2022-06-12  3:13     ` Sergey Senozhatsky
2022-06-12 23:02     ` John Ogness
2022-06-12 23:02       ` John Ogness
2022-06-13  3:49       ` Sergey Senozhatsky
2022-06-13  3:49         ` Sergey Senozhatsky
2022-06-13  8:30         ` John Ogness
2022-06-13  8:30           ` John Ogness
2022-06-13  9:05           ` Sergey Senozhatsky
2022-06-13  9:05             ` Sergey Senozhatsky
2022-06-13 10:14             ` Petr Mladek
2022-06-13 10:14               ` Petr Mladek
2022-06-13 16:11               ` David Laight
2022-06-13 16:11                 ` David Laight
2022-06-14  8:37                 ` Petr Mladek
2022-06-14  8:37                   ` Petr Mladek

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