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qemu-io: add option to enable tracing

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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 <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Stefan Hajnoczi 2012-03-12 16:36:07 +00:00 committed by Kevin Wolf
parent 3948d1d487
commit d7bb72c83c
1 changed files with 9 additions and 1 deletions
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10
qemu-io.c
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@ -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);