From mboxrd@z Thu Jan  1 00:00:00 1970
From: Dario Faggioli <dario.faggioli@citrix.com>
Subject: Re: [PATCH 06/15] xen: trace IRQ enabling/disabling
Date: Thu, 8 Jun 2017 18:11:16 +0200
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To: George Dunlap <george.dunlap@citrix.com>, xen-devel@lists.xenproject.org
Cc: Stefano Stabellini <sstabellini@kernel.org>, George Dunlap <george.dunlap@eu.citrix.com>, Andrew Cooper <andrew.cooper3@citrix.com>, Jennifer Herbert <jennifer.herbert@citrix.com>, Julien Grall <julien.grall@arm.com>, Jan Beulich <jbeulich@suse.com>
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On Thu, 2017-06-08 at 17:01 +0100, George Dunlap wrote:
> On 01/06/17 18:34, Dario Faggioli wrote:
> > diff --git a/xen/Kconfig.debug b/xen/Kconfig.debug
> > index 374c1c0..81910c9 100644
> > --- a/xen/Kconfig.debug
> > +++ b/xen/Kconfig.debug
> > @@ -98,7 +98,7 @@ config PERF_ARRAYS
> > =C2=A0	---help---
> > =C2=A0	=C2=A0=C2=A0Enables software performance counter array histogram=
s.
> > =C2=A0
> > -config TRACING
> > +menuconfig TRACING
> > =C2=A0	bool "Tracing"
> > =C2=A0	default y
> > =C2=A0	---help---
> > @@ -106,6 +106,15 @@ config TRACING
> > =C2=A0	=C2=A0=C2=A0in per-CPU ring buffers. The 'xentrace' tool can be =
used
> > to read
> > =C2=A0	=C2=A0=C2=A0the buffers and dump the content on the disk.
> > =C2=A0
> > +config TRACE_IRQSOFF
> > +	bool "Trace when IRQs are disabled and (re)enabled" if
> > EXPERT =3D "y"
> > +	default n
> > +	depends on TRACING
> > +	---help---
> > +	=C2=A0=C2=A0Makes it possible to generate events _every_ time IRQs
> > are disabled
> > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0and (re)en=
abled, with also an indication of where that
> > happened.
> > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0Note that =
this comes with high overead and produces huge
> > amount of
> > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0tracing da=
ta.
>=20
> I think I might emphasize that the overhead well be present even when
> tracing is off.=C2=A0=C2=A0What about something like this?
>=20
Yes, good point.

> "Note that this comes with an overhead even when tracing is disabled;
> and has a high overhead and produces a large amount of tracing data
> when
> enabled."
>=20
I like it, I'll go for it.

> With that change:
>=20
> Acked-by: George Dunlap <george.dunlap@citrix.com>
>=20
Thanks and Regards,
Dario
--=20
<<This happens because I choose it to happen!>> (Raistlin Majere)
-----------------------------------------------------------------
Dario Faggioli, Ph.D, http://about.me/dario.faggioli
Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)
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