Re: RFC: Lightweight tracing mechanism

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 





On Mon, Jun 12, 2017 at 12:40 AM Marc-André Lureau <marcandre.lureau@xxxxxxxxx> wrote:
Hi

On Fri, Jun 9, 2017 at 10:08 PM Jonathon Jongsma <jjongsma@xxxxxxxxxx> wrote:
On Fri, 2017-06-09 at 12:11 -0400, Marc-André Lureau wrote:
> >
>
> ----- Original Message -----
> >
> > > On 9 Jun 2017, at 17:16, Jonathon Jongsma <jjongsma@xxxxxxxxxx>
> > > wrote:
> > >
> > > On Fri, 2017-06-09 at 10:59 +0200, Christophe de Dinechin wrote:
> > > > > > What I see on the thread:
> > > > > > - log categorization. This was similar to Djasa bug but I
> > > > > > think
> > > > > > he just
> > > > > >   proposed to use domains in the glib log sense;
> > > >
> > > > Punchcard analogy: “Printer sheet categorization. This was
> > > > similar to
> > > > the report that Djisktra had taken McCarthy's listing by
> > > > mistake"
> > > >
> > > > I thought it was a good idea to derive glib log domains
> > > > automatically
> > > > from spice-traces.def. So it’s there in the branch now. That
> > > > being
> > > > said, as noted above, glib does linear searches on domain
> > > > names, so
> > > > this does not scale well. In the long term, we may want to have
> > > > a
> > > > separate field in a structured log.
> > >
> > >
> > > Responding only to this point for the moment: I don't think using
> > > multiple glib logging domains is necessarily desirable. We
> > > already use
> > > several logging domains, but the vast majority of logging
> > > statements
> > > within each project use a single domain. In spice-server, that
> > > primary
> > > log domain is "Spice", and in spice-gtk that domain is "GSpice".
> > > spice-
> > > server also has some additional domains like "SpiceWorker" and
> > > "SpiceDispatcher". spice-gtk also has GSpiceController (which
> > > isn't
> > > really used much these days).
> > >
> > > The problem is that both spice-server and spice-gtk have a way to
> > > enable debugging with an environment variable. But the code for
> > > enabling the debugging only actually enables the primary domain.
> >
> > The ‘traces’ branch enables all trace-related domains if you enable
> > debug.
> >
> > > So anything that is logged under a different domain does not get
> > > enabled.
> > > (In fact, spice-gtk has 2 ways to enable logging with an
> > > environment
> > > variable but one of the methods is the same one used for spice-
> > > server,
> > > but it doesn't work since it actually enables logging for the
> > > "Spice"
> > > domain which spice-gtk doesn't use.) I'm hoping to send some
> > > patches to
> > > clean up this mess soon.
> >
> > Ah, so I was not the only one thinking this was a mess :-)
>
> The mess comes because spice-gtk and spice server used different
> logging, when spice didn't depend on glib.
>
> The cleanup isn't over I suppose (Christophe F. did the move to glog
> in spice-common). 
>
> I don't get the problem with spice-gtk logging though.
>


Yes, there are historical reasons. And "mess" was an exaggeration. But
in the process of consolidating the implementations, we seem to have
introduced some inconsistencies. I'll send more details soon, I hope.

Some of them I just found out by reading spice-common log.c, introduced when switching to glog:

            debug_env = (char *)g_getenv("G_MESSAGES_DEBUG");
            if (debug_env == NULL) {
                g_setenv("G_MESSAGES_DEBUG", SPICE_LOG_DOMAIN, FALSE);
            } else {
                debug_env = g_strconcat(debug_env, ":", SPICE_LOG_DOMAIN, NULL);
                g_setenv("G_MESSAGES_DEBUG", SPICE_LOG_DOMAIN, FALSE);
                g_free(debug_env);
            }

- appending to G_MESSAGES_DEBUG is buggy, it's not using the newly built debug_env.
- this will only append the default "Spice" SPICE_LOG_DOMAIN (not the other spice sub-domains),
- the variable expects a space-seperated list (you sent a patch for that)
(+ the unnecessary cast, could just use another variable...)

+  it doesn't overwrite the value! :)

--
Marc-André Lureau
_______________________________________________
Spice-devel mailing list
Spice-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/spice-devel

[Index of Archives]     [Linux ARM Kernel]     [Linux ARM]     [Linux Omap]     [Fedora ARM]     [IETF Annouce]     [Security]     [Bugtraq]     [Linux]     [Linux OMAP]     [Linux MIPS]     [ECOS]     [Asterisk Internet PBX]     [Linux API]     [Monitors]