Hi Peter,
On 24/02/2016:05:02:41 PM, Peter Zijlstra wrote:
> On Wed, Feb 24, 2016 at 03:02:39PM +0100, Peter Zijlstra wrote:
> > FWIW, it would be nice to have a similar test for:
+ Michael, (C Test case for following proposed test case is at the end)
> >
> > attr = {
> > .disabled = true;
> > }
> >
> > sys_perf_event_open(&attr, .pid = self);
> >
> > if (attr.disabled)
> > ioctl(ENABLE);
> >
> > /* generate N events */
> >
> > ioctl(DISABLE);
> >
> > read();
> >
> > /* print event cnt and scale factors */
> >
> > and one that has .disabled = false.
>
>
> root@ivb-ep:~/perf# ./main
> 1000000903 218851613 218851613
> root@ivb-ep:~/perf# ./main 1
> 1000000235 218981231 218981231
>
>
> Appears to work...
Thanks, Picked patches from your new series and it worked :-)
# perf stat -x';' -e 'probe_exact:*' examples/exact_counts
65535;;probe_exact:f_65535x;85984820;100.00
997;;probe_exact:f_997x;85984820;100.00
103;;probe_exact:f_103x;85984820;100.00
3;;probe_exact:f_3x;85984820;100.00
2;;probe_exact:f_2x;85984820;100.00
1;;probe_exact:f_1x;85984820;100.00
~Pratyush
>
> ---
>
> #define _GNU_SOURCE
> #include <unistd.h>
> #include <stdio.h>
> #include <stdlib.h>
> #include <stdarg.h>
>
> #include "perf.h"
>
> static struct perf_event_attr perf_attr = {
> .type = PERF_TYPE_HARDWARE,
> .config = PERF_COUNT_HW_INSTRUCTIONS,
> .read_format = PERF_FORMAT_TOTAL_TIME_ENABLED |
> PERF_FORMAT_TOTAL_TIME_RUNNING,
> .exclude_kernel = 1,
> .pinned = 1,
> };
>
> void die(const char *err, ...)
> {
> va_list params;
>
> va_start(params, err);
> vfprintf(stderr, err, params);
> va_end(params);
>
> exit(-1);
> }
>
> int main (int argc, char **argv)
> {
> u64 val[3];
> int i, fd;
>
> perf_attr.disabled = argc > 1;
>
> fd = sys_perf_event_open(&perf_attr, 0, -1, -1, 0);
> if (fd < 0)
> die("failed to create perf_event");
>
> if (perf_attr.disabled)
> ioctl(fd, PERF_EVENT_IOC_ENABLE, 0);
>
> for (i = 0; i < 100000000; i++) {
> asm volatile ("nop\n\r"
> "nop\n\r"
> "nop\n\r"
> "nop\n\r"
> "nop\n\r"
> "nop\n\r"
> "nop\n\r");
> }
>
> ioctl(fd, PERF_EVENT_IOC_DISABLE, 0);
>
> read(fd, &val, sizeof(val));
>
> printf("%Lu %Lu %Lu\n", val[0], val[1], val[2]);
>
> return 0;
> }
