make bitehist a simpler example of log2 histograms
diff --git a/examples/bitehist_example.txt b/examples/bitehist_example.txt
index 5af66e1..a12e10f 100644
--- a/examples/bitehist_example.txt
+++ b/examples/bitehist_example.txt
@@ -1,70 +1,25 @@
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 | |
+ value : count distribution
+ 0 -> 1 : 3 | |
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 | |
- 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 |******* |
+ 32 -> 63 : 0 | |
+ 64 -> 127 : 1 | |
+ 128 -> 255 : 800 |**************************************|
- kbytes : count distribution
- 0 -> 1 : 0 | |
- 2 -> 3 : 0 | |
- 4 -> 7 : 4 |**************************************|
+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.
-
-Full usage:
-
-# ./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.