def test_perf_buffer_for_each_cpu(self):
self.events = []
class Data(ct.Structure):
_fields_ = [("cpu", ct.c_ulonglong)]
def cb(cpu, data, size):
self.assertGreater(size, ct.sizeof(Data))
event = ct.cast(data, ct.POINTER(Data)).contents
self.events.append(event)
def lost_cb(lost):
self.assertGreater(lost, 0)
text = """
BPF_PERF_OUTPUT(events);
int kprobe__sys_nanosleep(void *ctx) {
struct {
u64 cpu;
} data = {bpf_get_smp_processor_id()};
events.perf_submit(ctx, &data, sizeof(data));
return 0;
}
"""
b = BPF(text=text)
b["events"].open_perf_buffer(cb, lost_cb=lost_cb)
online_cpus = get_online_cpus()
for cpu in online_cpus:
subprocess.call(['taskset', '-c', str(cpu), 'sleep', '0.1'])
b.kprobe_poll()
b.cleanup()
self.assertGreaterEqual(
len(self.events), len(online_cpus),
'Received only {}/{} events'.format(len(self.events),
len(online_cpus)))
def test_perf_buffer_for_each_cpu(self):
self.events = []
class Data(ct.Structure):
_fields_ = [("cpu", ct.c_ulonglong)]
def cb(cpu, data, size):
self.assertGreater(size, ct.sizeof(Data))
event = ct.cast(data, ct.POINTER(Data)).contents
self.events.append(event)
text = """
BPF_PERF_OUTPUT(events);
int kprobe__sys_nanosleep(void *ctx) {
struct {
u64 cpu;
} data = {bpf_get_smp_processor_id()};
events.perf_submit(ctx, &data, sizeof(data));
return 0;
}
"""
b = BPF(text=text)
b["events"].open_perf_buffer(cb)
online_cpus = get_online_cpus()
for cpu in online_cpus:
subprocess.call(['taskset', '-c', str(cpu), 'sleep', '0.1'])
b.kprobe_poll()
b.cleanup()
self.assertGreaterEqual(len(self.events), len(online_cpus), 'Received only {}/{} events'.format(len(self.events), len(online_cpus)))
def test_get_online_cpus(self):
online_cpus = get_online_cpus()
num_cores = multiprocessing.cpu_count()
self.assertEqual(len(online_cpus), num_cores)
output.perf_submit(ctx, &perf_data, sizeof(struct perf_delta));
}
"""
usage='Usage: ipc.py [options]\nexample ./ipc.py -l c -s strlen'
parser = OptionParser(usage)
parser.add_option('-l', '--lib', dest='lib_name', help='lib name containing symbol to trace, e.g. c for libc', type=str)
parser.add_option('-s', '--sym', dest='sym', help='symbol to trace', type=str)
(options, args) = parser.parse_args()
if (not options.lib_name or not options.sym):
parser.print_help()
exit()
num_cpus = len(utils.get_online_cpus())
b = BPF(text=code, cflags=['-DMAX_CPUS=%s' % str(num_cpus)])
# Attach Probes at start and end of the trace function
# NOTE: When attaching to a function for tracing, during runtime relocation
# stage by linker, function will be called once to return a different function
# address, which will be called by the process. e.g. in case of strlen
# after relocation stage, __strlen_sse2 is called instread of strlen.
# NOTE: There will be a context switch from userspace to kernel space,
# on caputring counters on USDT probes, so actual IPC might be slightly different.
# This example is to give a reference on how to use perf events with tracing.
b.attach_uprobe(name=options.lib_name, sym=options.sym, fn_name="trace_start")
b.attach_uretprobe(name=options.lib_name, sym=options.sym, fn_name="trace_end")
def print_data(cpu, data, size):
def test_get_online_cpus(self):
online_cpus = get_online_cpus()
num_cores = multiprocessing.cpu_count()
self.assertEqual(len(online_cpus), num_cores)