Re: [Qemu-devel] [PATCH 3/5] trace-cmd: Support trace-agent of virtio-trace

[Yoshihiro YUNOMAE]

Hi Steven,

(2012/08/22 22:51), Steven Rostedt wrote:
> On Wed, 2012-08-22 at 17:43 +0900, Yoshihiro YUNOMAE wrote:
> > Add read path and control path to use trace-agent of virtio-trace.
> > When we use trace-agent, trace-cmd will be used as follows:
> >         # AGENT_READ_DIR=/tmp/virtio-trace/tracing \
> >           AGENT_CTL=/tmp/virtio-trace/agent-ctl-path.in \
> >           TRACING_DIR=/tmp/virtio-trace/debugfs/tracing \\
>
> Ha! You used "TRACING_DIR" but patch one introduces TRACE_DIR. Lets
> change this to DEBUG_TRACING_DIR instead anyway.

Oh, sorry for the confusion.

> Also, I don't like the generic environment variables. Perhaps
> VIRTIO_TRACE_DIR, or AGENT_TRACE_DIR and AGENT_TRACE_CTL. Lets try to
> keep the environment namespace sparse.

OK, I'll change these name of environment variables as follows:
    AGENT_READ_DIR
    AGENT_TRACE_CTL
    GUEST_TRACING_DIR

> >           trace-cmd record -e "sched:*"
> > Here, AGENT_READ_DIR is the path for a reading directory of virtio-trace,
> > AGENT_CTL is a control path of trace-agent, and TRACING_DIR is a debugfs path
> > of a guest.
> >
> > Signed-off-by: Yoshihiro YUNOMAE <address@hidden>
> > ---
> >
> >   trace-cmd.h      |    1 +
> >   trace-recorder.c |   57 +++++++++++++++++++++++++++++++++++++++++++++++++++++-
> >   trace-util.c     |   18 +++++++++++++++++
> >   3 files changed, 75 insertions(+), 1 deletions(-)
> >
> > diff --git a/trace-cmd.h b/trace-cmd.h
> > index f904dc5..75506ed 100644
> > --- a/trace-cmd.h
> > +++ b/trace-cmd.h
> > @@ -72,6 +72,7 @@ static inline int tracecmd_host_bigendian(void)
> >   }
> >
> >   char *tracecmd_find_tracing_dir(void);
> > +char *guest_agent_tracing_read_dir(void);
> >
> >   /* --- Opening and Reading the trace.dat file --- */
> >
> > diff --git a/trace-recorder.c b/trace-recorder.c
> > index 215affc..3b750e9 100644
> > --- a/trace-recorder.c
> > +++ b/trace-recorder.c
> > @@ -33,6 +33,7 @@
> >   #include <unistd.h>
> >   #include <ctype.h>
> >   #include <errno.h>
> > +#include <stdbool.h>
> >
> >   #include "trace-cmd.h"
> >
> > @@ -43,6 +44,8 @@ struct tracecmd_recorder {
> >         int             page_size;
> >         int             cpu;
> >         int             stop;
> > +       int             ctl_fd;
> > +       bool            agent_existing;
>
> Thanks for the reminder. I need to convert a lot to use 'bool' instead.

I'll change 'int' just for flag to use 'bool' as much as possible
after finishing this patch set.

> >   };
> >
> >   void tracecmd_free_recorder(struct tracecmd_recorder *recorder)
> > @@ -59,11 +62,29 @@ void tracecmd_free_recorder(struct tracecmd_recorder 
> > *recorder)
> >         free(recorder);
> >   }
> >
> > +static char *use_trace_agent_dir(char *ctl_path,
> > +                                       struct tracecmd_recorder *recorder)
> > +{
> > +       ctl_path = strdup(ctl_path);
> > +       if (!ctl_path)
> > +               die("malloc");
> > +       warning("Use environmental control path: %s\n", ctl_path);
>
> s/Use/Using/

OK, I'll correct this.

Thank you,

--
Yoshihiro YUNOMAE
Software Platform Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: address@hidden