Re: [Qemu-devel] [PATCH] qemu-io: add option to enable tracing

[Stefan Hajnoczi]

On Wed, Dec 21, 2011 at 3:35 PM, Stefan Hajnoczi
<address@hidden> wrote:

Ping?  Do you want to take this through the block tree?

> It can be useful to enable QEMU tracing when trying out block layer
> interfaces via qemu-io.  Tracing can be enabled using the new -t FILE
> option where the given file contains a list of trace events to enable
> (just like the qemu --trace events=FILE option).
>
>  $ echo qemu_vfree >my-events
>  $ ./qemu-io -t my-events ...
>
> Remember to use ./configure --enable-trace-backend=BACKEND when building
> qemu-io.
>
> Signed-off-by: Stefan Hajnoczi <address@hidden>
> ---
>  qemu-io.c |    8 +++++++-
>  1 files changed, 7 insertions(+), 1 deletions(-)
>
> diff --git a/qemu-io.c b/qemu-io.c
> index ffa62fb..ad91fd6 100644
> --- a/qemu-io.c
> +++ b/qemu-io.c
> @@ -17,6 +17,7 @@
>  #include "qemu-common.h"
>  #include "block_int.h"
>  #include "cmd.h"
> +#include "trace/control.h"
>
>  #define VERSION        "0.0.1"
>
> @@ -1722,6 +1723,7 @@ static void usage(const char *name)
>  "  -g, --growable       allow file to grow (only applies to protocols)\n"
>  "  -m, --misalign       misalign allocations for O_DIRECT\n"
>  "  -k, --native-aio     use kernel AIO implementation (on Linux only)\n"
> +"  -t, --trace FILE     enable trace events listed in the given file\n"
>  "  -h, --help           display this help and exit\n"
>  "  -V, --version        output version information and exit\n"
>  "\n",
> @@ -1733,7 +1735,7 @@ int main(int argc, char **argv)
>  {
>     int readonly = 0;
>     int growable = 0;
> -    const char *sopt = "hVc:rsnmgk";
> +    const char *sopt = "hVc:rsnmgkt:";
>     const struct option lopt[] = {
>         { "help", 0, NULL, 'h' },
>         { "version", 0, NULL, 'V' },
> @@ -1745,6 +1747,7 @@ int main(int argc, char **argv)
>         { "misalign", 0, NULL, 'm' },
>         { "growable", 0, NULL, 'g' },
>         { "native-aio", 0, NULL, 'k' },
> +        { "trace", 1, NULL, 't' },
>         { NULL, 0, NULL, 0 }
>     };
>     int c;
> @@ -1776,6 +1779,9 @@ int main(int argc, char **argv)
>         case 'k':
>             flags |= BDRV_O_NATIVE_AIO;
>             break;
> +        case 't':
> +            trace_backend_init(optarg, NULL);
> +            break;
>         case 'V':
>             printf("%s version %s\n", progname, VERSION);
>             exit(0);
> --
> 1.7.7.3
>
>