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Commit 489e4f52 authored by Brenden Blanco's avatar Brenden Blanco
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Merge pull request #185 from brendangregg/master 

print_log2_hist() for #143
parents 4135be22 e845c520
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Showing with 90 additions and 187 deletions
examples/bitehist.py
View file @ 489e4f52
......@@ -5,8 +5,6 @@
#
# Written as a basic example of using a histogram to show a distribution.
#
# USAGE: bitehist.py [interval [count]]
#
# The default interval is 5 seconds. A Ctrl-C will print the partially
# gathered histogram then exit.
#
......@@ -16,90 +14,19 @@
# 15-Aug-2015 Brendan Gregg Created this.
from bcc import BPF
from ctypes import c_ushort, c_int, c_ulonglong
from time import sleep
from sys import argv
def usage():
print("USAGE: %s [interval [count]]" % argv[0])
exit()
# arguments
interval = 5
count = -1
if len(argv) > 1:
try:
interval = int(argv[1])
if interval == 0:
raise
if len(argv) > 2:
count = int(argv[2])
except: # also catches -h, --help
usage()
# load BPF program
b = BPF(src_file = "bitehist.c")
b.attach_kprobe(event="blk_start_request", fn_name="do_request")
dist_max = 64
# header
print("Tracing... Hit Ctrl-C to end.")
# functions
stars_max = 38
def stars(val, val_max, width):
i = 0
text = ""
while (1):
if (i > (width * val / val_max) - 1) or (i > width - 1):
break
text += "*"
i += 1
if val > val_max:
text = text[:-1] + "+"
return text
def print_log2_hist(dist, val_type):
idx_max = -1
val_max = 0
for i in range(1, dist_max + 1):
try:
val = dist[c_int(i)].value
if (val > 0):
idx_max = i
if (val > val_max):
val_max = val
except:
break
if idx_max > 0:
print(" %-15s : count distribution" % val_type);
for i in range(1, idx_max + 1):
low = (1 << i) >> 1
high = (1 << i) - 1
if (low == high):
low -= 1
try:
val = dist[c_int(i)].value
print("%8d -> %-8d : %-8d |%-*s|" % (low, high, val,
stars_max, stars(val, val_max, stars_max)))
except:
break
# output
loop = 0
do_exit = 0
while (1):
if count > 0:
loop += 1
if loop > count:
exit()
try:
sleep(interval)
except KeyboardInterrupt:
pass; do_exit = 1
try:
sleep(99999999)
except KeyboardInterrupt:
print
print_log2_hist(b["dist"], "kbytes")
b["dist"].clear()
if do_exit:
exit()
b["dist"].print_log2_hist()
examples/bitehist_example.txt
View file @ 489e4f52
Demonstrations of bitehist.py, the Linux eBPF/bcc version.
This prints a power-of-2 histogram to show the block I/O size distribution.
By default, a summary is printed every five seconds:
A summary is printed after Ctrl-C is hit.
# ./bitehist.py
# ./bitehist.py
Tracing... Hit Ctrl-C to end.
kbytes : count distribution
0 -> 1 : 0 | |
2 -> 3 : 0 | |
4 -> 7 : 26 |************* |
8 -> 15 : 3 |* |
16 -> 31 : 5 |** |
32 -> 63 : 6 |*** |
64 -> 127 : 7 |*** |
128 -> 255 : 75 |**************************************|
kbytes : count distribution
0 -> 1 : 0 | |
2 -> 3 : 0 | |
4 -> 7 : 83 |**************************************|
8 -> 15 : 2 | |
16 -> 31 : 6 |** |
32 -> 63 : 6 |** |
64 -> 127 : 5 |** |
128 -> 255 : 21 |********* |
^C
kbytes : count distribution
0 -> 1 : 0 | |
2 -> 3 : 0 | |
4 -> 7 : 8 |**************************************|
The first output shows a bimodal distribution. The largest mode of 75 I/O were
between 128 and 255 Kbytes in size, and another mode of 26 I/O were between 4
and 7 Kbytes in size.
The next output summary shows the workload is doing more 4 - 7 Kbyte I/O.
The final output is partial, showing what was measured until Ctrl-C was hit.
For an output interval of one second, and three summaries:
# ./bitehist.py 1 3
Tracing... Hit Ctrl-C to end.
kbytes : count distribution
0 -> 1 : 0 | |
value : count distribution
0 -> 1 : 3 | |
2 -> 3 : 0 | |
4 -> 7 : 4 |**************************************|
kbytes : count distribution
0 -> 1 : 0 | |
2 -> 3 : 0 | |
4 -> 7 : 5 |**************************************|
4 -> 7 : 211 |********** |
8 -> 15 : 0 | |
16 -> 31 : 0 | |
32 -> 63 : 1 |******* |
kbytes : count distribution
0 -> 1 : 0 | |
2 -> 3 : 0 | |
4 -> 7 : 4 |**************************************|
32 -> 63 : 0 | |
64 -> 127 : 1 | |
128 -> 255 : 800 |**************************************|
Full usage:
This output shows a bimodal distribution. The largest mod of 800 I/O were
between 128 and 255 Kbytes in size, and another mode of 211 I/O were between
4 and 7 Kbytes in size.
# ./bitehist.py -h
USAGE: ./bitehist.py [interval [count]]
Understanding this distribution is useful for characterizing workloads and
understanding performance. The existance of this distribution is not visible
from averages alone.
examples/hello_world.py
View file @ 489e4f52
......@@ -4,15 +4,10 @@
# run in project examples directory with:
# sudo ./hello_world.py"
# see trace_fields.py for a longer example
from bcc import BPF
prog = """
int hello(void *ctx) {
bpf_trace_printk("Hello, World!\\n");
return 0;
}
"""
b = BPF(text=prog)
b = BPF(text='void hello(void *ctx) { bpf_trace_printk("Hello, World!\\n"); }')
b.attach_kprobe(event="sys_clone", fn_name="hello")
b.trace_print(fmt="{1} {5}")
b.trace_print()
examples/trace_fields.py 0 → 100755
View file @ 489e4f52
#!/usr/bin/env python
# Copyright (c) PLUMgrid, Inc.
# Licensed under the Apache License, Version 2.0 (the "License")
# This is an example of tracing an event and printing custom fields.
# run in project examples directory with:
# sudo ./trace_fields.py"
from bcc import BPF
prog = """
int hello(void *ctx) {
bpf_trace_printk("Hello, World!\\n");
return 0;
}
"""
b = BPF(text=prog)
b.attach_kprobe(event="sys_clone", fn_name="hello")
print "PID MESSAGE"
b.trace_print(fmt="{1} {5}")
examples/vfsreadlat.py
View file @ 489e4f52
......@@ -41,51 +41,10 @@ if len(argv) > 1:
b = BPF(src_file = "vfsreadlat.c")
b.attach_kprobe(event="vfs_read", fn_name="do_entry")
b.attach_kretprobe(event="vfs_read", fn_name="do_return")
dist_max = 64
# header
print("Tracing... Hit Ctrl-C to end.")
# functions
stars_max = 38
def stars(val, val_max, width):
i = 0
text = ""
while (1):
if (i > (width * val / val_max) - 1) or (i > width - 1):
break
text += "*"
i += 1
if val > val_max:
text = text[:-1] + "+"
return text
def print_log2_hist(dist, val_type):
idx_max = -1
val_max = 0
for i in range(1, dist_max + 1):
try:
val = dist[c_int(i)].value
if (val > 0):
idx_max = i
if (val > val_max):
val_max = val
except:
break
if idx_max > 0:
print(" %-15s : count distribution" % val_type);
for i in range(1, idx_max + 1):
low = (1 << i) >> 1
high = (1 << i) - 1
if (low == high):
low -= 1
try:
val = dist[c_int(i)].value
print("%8d -> %-8d : %-8d |%-*s|" % (low, high, val,
stars_max, stars(val, val_max, stars_max)))
except:
break
# output
loop = 0
do_exit = 0
......@@ -100,7 +59,7 @@ while (1):
pass; do_exit = 1
print
print_log2_hist(b["dist"], "usecs")
b["dist"].print_log2_hist("usecs")
b["dist"].clear()
if do_exit:
exit()
src/python/bcc/__init__.py
View file @ 489e4f52
......@@ -95,6 +95,7 @@ KALLSYMS = "/proc/kallsyms"
ksym_addrs = []
ksym_names = []
ksym_loaded = 0
stars_max = 38
@atexit.register
def cleanup_kprobes():
......@@ -220,6 +221,52 @@ class BPF(object):
else:
super(BPF.Table, self).clear()
@staticmethod
def _stars(val, val_max, width):
i = 0
text = ""
while (1):
if (i > (width * val / val_max) - 1) or (i > width - 1):
break
text += "*"
i += 1
if val > val_max:
text = text[:-1] + "+"
return text
def print_log2_hist(self, val_type="value"):
"""print_log2_hist(type=value)
Prints a table as a log2 histogram. The table must be stored as
log2. The type argument is optional, and is a column header.
"""
global stars_max
log2_dist_max = 64
idx_max = -1
val_max = 0
for i in range(1, log2_dist_max + 1):
try:
val = self[ct.c_int(i)].value
if (val > 0):
idx_max = i
if (val > val_max):
val_max = val
except:
break
if idx_max > 0:
print(" %-15s : count distribution" % val_type);
for i in range(1, idx_max + 1):
low = (1 << i) >> 1
high = (1 << i) - 1
if (low == high):
low -= 1
try:
val = self[ct.c_int(i)].value
print("%8d -> %-8d : %-8d |%-*s|" % (low, high, val,
stars_max, self._stars(val, val_max, stars_max)))
except:
break
def __iter__(self):
return BPF.Table.Iter(self, self.Key)
......
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