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Date: Mon, 22 Aug 2005 15:38:38 -0700
From: Andrew Morton <akpm@osdl.org>
To: tony.luck@intel.com
Cc: davem@davemloft.net, jasonuhl@sgi.com, linux-kernel@vger.kernel.org
Subject: Re: CONFIG_PRINTK_TIME woes
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tony.luck@intel.com wrote:
>
> >How fast is printk?  I haven't looked.
> >
> >ie: if you do back-to-back printk's, what's the timestamp increment?
> 
> On ia64 it looks like about 4-5 usec increment for back-to-back
> printk (with no serial console configured, and dmesg -n to turn
> off messages to the VGA console).
> 

Ah, thanks.  Presumably it'll be considerably longer with %d's and %s's in
there.  But still, ~10 usecs is good resolution for I/O operations.