From mboxrd@z Thu Jan  1 00:00:00 1970
From: mmcternan@airvana.com (Mike McTernan)
Date: Tue, 2 Feb 2010 21:12:38 -0000
Subject: [ltt-dev] trace_clock_update() spinning
In-Reply-To: <20100202194228.GA24026@Krystal>
References: <4B3F8896E1733D4787DDB0EA1C7FF91F0108CDD1@ukmail.uk.wirelessworld.airvananet.com>
	<20100202194228.GA24026@Krystal>
Message-ID: <4B3F8896E1733D4787DDB0EA1C7FF91F0108CDDF@ukmail.uk.wirelessworld.airvananet.com>

> Mathieu Desnoyers wrote:
>
> So it's not that LTTng itself is taking time, but that the trace clock
> resolution available for your architecture is really coarse. 

Excellent!  I understand what that means now.  Everything in the trace
is crushed up using the bottom 13-bits of the counter advanced with each
marker, then at the instance the upper bits are updated on the timer
tick the output appears to jump along making it _look_ like the update
function took all the remaining time.  What a fool I was!

> You could possibly get a better resolution by creating a trace clock
> specific for your architecture.

I'm pretty sure there's a general purpose timer hanging around somewhere
on this board if I can't find some sort of performance counter register
with which to improve things.

Many Thanks,

Mike