Re: Printk mulitple line message support

From: Joe Perches
Date: Mon Nov 14 2011 - 09:40:41 EST


On Mon, 2011-11-14 at 14:58 +0800, Huang Ying wrote:
> Hi,
>
> In most cases, printk only guarantees messages from different printk
> calling will not be interleaved between each other. But many printk
> users uses multiple line to form a complete message and call printk
> for each line. So the following situation is possible for two printk
> users running on two CPUs.
>
> line 1 of message from printk user1
> line 1 of message from printk user2
> line 2 of message from printk user1
> line 2 of message from printk user2
>
> This makes kernel log hard to read. One possible solution to this
> issue is to give a sequence number (or ID) to each complete message.
> So the above lines will be:
>
> {1}line 1 of message from printk user1
> {2}line 1 of message from printk user2
> {1}line 2 of message from printk user1
> {2}line 2 of message from printk user2
>
> Then some simple script can be used to group lines together according
> to sequence number in lines.
>
> What do you think about that?

This makes the typical multi-part but non-interleaved
output difficult to read.

How about determining if there is interleaving and
emitting sequence # only in those cases?

Perhaps test the atomic for the last sequence #.


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