scripts/kvm/kvm_stat: Cleanup and pre-init perf_event_attr

All initializations of the ctypes struct that don't need additional
information were moved to its init method. The unneeded
initializations for sample_type and sample_period were removed as they
do not affect the counters that are read.

This improves readability of the setup_event_attribute by halfing its
LOC.

Signed-off-by: Janosch Frank <frankja@linux.vnet.ibm.com>
Message-Id: <1452525484-32309-30-git-send-email-frankja@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Janosch Frank 2016-01-11 16:17:59 +01:00 committed by Paolo Bonzini
parent c887d9a25e
commit 00842aaca5

View File

@ -331,6 +331,13 @@ class perf_event_attr(ctypes.Structure):
('bp_addr', ctypes.c_uint64),
('bp_len', ctypes.c_uint64),
]
def __init__(self):
super(self.__class__, self).__init__()
self.type = PERF_TYPE_TRACEPOINT
self.size = ctypes.sizeof(self)
self.read_format = PERF_FORMAT_GROUP
def perf_event_open(attr, pid, cpu, group_fd, flags):
return syscall(ARCH.sc_perf_evt_open, ctypes.pointer(attr),
ctypes.c_int(pid), ctypes.c_int(cpu),
@ -369,11 +376,7 @@ class Event(object):
trace_point, 'id')
event_attr = perf_event_attr()
event_attr.type = PERF_TYPE_TRACEPOINT
event_attr.size = ctypes.sizeof(event_attr)
event_attr.config = int(open(id_path).read())
event_attr.sample_period = 1
event_attr.read_format = PERF_FORMAT_GROUP
return event_attr
def setup_event(self, group, trace_cpu, trace_point, trace_filter,