diff options
author | Wei Huang <wei@redhat.com> | 2015-01-23 15:56:04 -0500 |
---|---|---|
committer | Paolo Bonzini <pbonzini@redhat.com> | 2015-01-26 12:27:05 +0100 |
commit | fc116efad0aadb2f8a49d51240bddbfe21b631a0 (patch) | |
tree | b23457793d38d52d98f884ea96bc206a19fda762 /scripts | |
parent | 13704e4c455770d500d6b87b117e32f0d01252c9 (diff) |
kvm_stat: Add RESET support for perf event ioctl
While running kvm_stat using tracepoint on ARM64 hardware (e.g. "kvm_stat
-1 -t"), the initial values of some kvm_userspace_exit counters were found
to be very suspecious. For instance the tracing tool showed that S390_TSCH
was called many times on ARM64 machine, which apparently was wrong.
This patch adds RESET ioctl support for perf monitoring. Before calling
ioctl to enable a perf event, this patch resets the counter first. With
this patch, the init counter values become correct on ARM64 hardware.
Example:
==== before patch ====
kvm_userspace_exit(S390_SIEIC) 1426 0
kvm_userspace_exit(S390_TSCH) 339 0
==== after patch ====
kvm_userspace_exit(S390_SIEIC) 0 0
kvm_userspace_exit(S390_TSCH) 0 0
Signed-off-by: Wei Huang <wei@redhat.com>
Diffstat (limited to 'scripts')
-rwxr-xr-x | scripts/kvm/kvm_stat | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/scripts/kvm/kvm_stat b/scripts/kvm/kvm_stat index 8f6f00715e..c0c4ff0de3 100755 --- a/scripts/kvm/kvm_stat +++ b/scripts/kvm/kvm_stat @@ -186,6 +186,7 @@ ioctl_numbers = { 'SET_FILTER' : 0x40082406, 'ENABLE' : 0x00002400, 'DISABLE' : 0x00002401, + 'RESET' : 0x00002403, } def x86_init(flag): @@ -346,6 +347,9 @@ class Event(object): def disable(self): import fcntl fcntl.ioctl(self.fd, ioctl_numbers['DISABLE'], 0) + def reset(self): + import fcntl + fcntl.ioctl(self.fd, ioctl_numbers['RESET'], 0) class TracepointProvider(object): def __init__(self): @@ -405,6 +409,7 @@ class TracepointProvider(object): for group in self.group_leaders: for event in group.events: if event.name in fields: + event.reset() event.enable() else: event.disable() |