Commit d7bb72c8 authored by Stefan Hajnoczi's avatar Stefan Hajnoczi Committed by Kevin Wolf
Browse files

qemu-io: add option to enable tracing 



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: default avatarStefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent 3948d1d4

qemu-io.c

+9 −1
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
#include "qemu-common.h"

#include "block_int.h"

#include "cmd.h"

#include "trace/control.h"



#define VERSION	"0.0.1"
@@ -1783,6 +1784,7 @@ 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",
@@ -1794,7 +1796,7 @@ 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' },
@@ -1806,6 +1808,7 @@ 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;
@@ -1837,6 +1840,11 @@ int main(int argc, char **argv) 
        case 'k':

            flags |= BDRV_O_NATIVE_AIO;

            break;

        case 'T':

            if (!trace_backend_init(optarg, NULL)) {

                exit(1); /* error message will have been printed */

            }

            break;

        case 'V':

            printf("%s version %s\n", progname, VERSION);

            exit(0);