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Date: Wed, 21 Jun 2017 18:09:51 +0200
From: Andrew Lunn <andrew@lunn.ch>
To: Petr Mladek <pmladek@suse.com>
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Cc: Peter Zijlstra <peterz@infradead.org>,
	"ksummit-discuss@lists.linuxfoundation.org"
	<ksummit-discuss@lists.linuxfoundation.org>
Subject: Re: [Ksummit-discuss] [TECH TOPIC] printk redesign
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> 7. Unreliable time stamps and sorting messages
> 
>    The current extra buffers (cont, printk_safe, printk_safe_nmi)
>    makes this worse. The timestamp is added later.

All you need is a sequence number. Since you have the CPU number
already, it could be a per CPU atomic. And you probably don't even
need to sort the output, if the sequence number is part of the
output. How bad is the reordering? Would a sequence space of 256 be
enough?

	Andrew