Re: [Patch 00/15] Reduce tracing payload size.

[Andi Kleen]

On Mon, Dec 06, 2010 at 08:56:37AM -0500, Ted Ts'o wrote:
> On Mon, Dec 06, 2010 at 02:22:00PM +0100, Andi Kleen wrote:
> > David Sharp <dhsharp@xxxxxxxxxx> writes:
> > >
> > > These patches are just a start to shrinking the size of trace events. I am
> > > planning to also make small versions of trace events that are used when
> > > CONFIG_SMALL_TRACES is enabled. I'm also open to discussion of other ways to
> > > shrink event sizes.
> > 
> > Maybe the simplest would be to lzo them as they get logged?
> > I assume you already considered that?
> 
> The tracing subsystem is supposed to be extremely low-overhead.
> Compressiong the event log would add considerable CPU overhead.  If we

lzo as a rule of thumb is about as expensive as 3x memcpy()
That's not really expensive.

-Andi

-- 
ak@xxxxxxxxxxxxxxx -- Speaking for myself only.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/