Messages in this thread | | | Date | Wed, 13 May 2015 21:05:22 +0900 | From | Namhyung Kim <> | Subject | Re: [RFC/PATCH v2] perf data: Add stat subcommand to show sample event stat |
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Hi Andi,
On Mon, May 11, 2015 at 05:44:05PM +0200, Andi Kleen wrote: > > The sampling ratio was useful for me to determine how often the event > > was sampled - in this case the cpu cycles event was only sampled at 12% > > That's dangerous to determine without a plot. It could be that it was bimodal: > 100% busy and then idle. You may want to add something like the spark > plots I submitted for stat some time ago.
Right, we cannot know the exact situation from a single number. But it was okay for me just to see overall status from the number. This is what we cannot know from the output of 'perf report' easily, so I'd like to add this info in some way.
Anyway, I wrote a script to plot the number of samples and periods using python's matplotlib package. Maybe we can add it to the script database.
Thanks, Namhyung
/* sample-chart.py */ import os import sys import numpy as np import matplotlib.pyplot as plt
sys.path.append(os.environ['PERF_EXEC_PATH'] + \ '/scripts/python/Perf-Trace-Util/lib/Perf/Trace')
from perf_trace_context import * from EventClass import *
events = {} mode = None # 'cpu' or 'task' nr_events = 0 first_time = 0 last_time = 0
def trace_begin(): pass
def trace_end(): xcnt = last_time - first_time + 1 xpos = np.arange(xcnt) times = np.arange(first_time, last_time + 1)
fig, plt_array = plt.subplots(nrows = nr_events, ncols = 2) fig.suptitle("Event stat", fontsize=20)
n = 0 for e in events: p1 = plt_array[n][0] p2 = plt_array[n][1] for k in events[e]: # key = cpu or tid ev_stats = events[e][k]
samples = np.zeros(xcnt) periods = np.zeros(xcnt) for t in ev_stats: samples[t - first_time] = ev_stats[t][0] periods[t - first_time] = ev_stats[t][1]
key = "%s %d" % (mode, k)
p1.plot(times, samples, 'o', linewidth=2, label=key) p2.plot(times, periods, '-', linewidth=2, label=key)
expect = 400 * np.ones(xcnt) p1.plot(times, expect, '--')
p1.set_title("Number of samples in '%s'" % e) p1.legend() p2.set_title("Event values in '%s'" % e) p2.legend() n += 1
plt.show()
def process_event(param_dict): evt = param_dict["ev_name"] cpu = param_dict["sample"]["cpu"] tid = param_dict["sample"]["tid"] time = param_dict["sample"]["time"] / 100000000 # 100 ms val = param_dict["sample"]["period"]
if evt not in events: global nr_events nr_events += 1 events[evt] = {}
global mode if mode is None: if cpu >= 10000000: mode = 'task' else: mode = 'cpu'
key = cpu if mode == 'cpu' else tid if key not in events[evt]: events[evt][key] = {}
global first_time, last_time if first_time == 0 or first_time > time: first_time = time if last_time < time: last_time = time
ev_stat = events[evt][key] if time not in ev_stat: ev_stat[time] = [0, 0] # (nr_sample, period) ev_stat[time][0] += 1 ev_stat[time][1] += val
def trace_unhandled(event_name, context, event_fields_dict): pass
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