| Demonstrations of biotop, the Linux eBPF/bcc version. |
| |
| |
| Short for block device I/O top, biotop summarizes which processes are |
| performing disk I/O. It's top for disks. Sample output: |
| |
| # ./biotop |
| Tracing... Output every 1 secs. Hit Ctrl-C to end |
| |
| 08:04:11 loadavg: 1.48 0.87 0.45 1/287 14547 |
| |
| PID COMM D MAJ MIN DISK I/O Kbytes AVGms |
| 14501 cksum R 202 1 xvda1 361 28832 3.39 |
| 6961 dd R 202 1 xvda1 1628 13024 0.59 |
| 13855 dd R 202 1 xvda1 1627 13016 0.59 |
| 326 jbd2/xvda1-8 W 202 1 xvda1 3 168 3.00 |
| 1880 supervise W 202 1 xvda1 2 8 6.71 |
| 1873 supervise W 202 1 xvda1 2 8 2.51 |
| 1871 supervise W 202 1 xvda1 2 8 1.57 |
| 1876 supervise W 202 1 xvda1 2 8 1.22 |
| 1892 supervise W 202 1 xvda1 2 8 0.62 |
| 1878 supervise W 202 1 xvda1 2 8 0.78 |
| 1886 supervise W 202 1 xvda1 2 8 1.30 |
| 1894 supervise W 202 1 xvda1 2 8 3.46 |
| 1869 supervise W 202 1 xvda1 2 8 0.73 |
| 1888 supervise W 202 1 xvda1 2 8 1.48 |
| |
| By default the screen refreshes every 1 second, and shows the top 20 disk |
| consumers, sorted on total Kbytes. The first line printed is the header, |
| which has the time and then the contents of /proc/loadavg. |
| |
| For the interval summarized by the output above, the "cksum" command performed |
| 361 disk reads to the "xvda1" device, for a total of 28832 Kbytes, with an |
| average I/O time of 3.39 ms. Two "dd" processes were also reading from the |
| same disk, which a higher I/O rate and lower latency. While the average I/O |
| size is not printed, it can be determined by dividing the Kbytes column by |
| the I/O column. |
| |
| The columns through to Kbytes show the workload applied. The final column, |
| AVGms, shows resulting performance. Other bcc tools can be used to get more |
| details when needed: biolatency and biosnoop. |
| |
| Many years ago I created the original "iotop", and later regretted not calling |
| it diskiotop or blockiotop, as "io" alone is ambiguous. This time it is biotop. |
| |
| |
| The -C option can be used to prevent the screen from clearing (my preference). |
| Here's using it with a 5 second interval: |
| |
| # ./biotop -C 5 |
| Tracing... Output every 5 secs. Hit Ctrl-C to end |
| |
| 08:09:44 loadavg: 0.42 0.44 0.39 2/282 22115 |
| |
| PID COMM D MAJ MIN DISK I/O Kbytes AVGms |
| 22069 dd R 202 1 xvda1 5993 47976 0.33 |
| 326 jbd2/xvda1-8 W 202 1 xvda1 3 168 2.67 |
| 1866 svscan R 202 1 xvda1 33 132 1.24 |
| 1880 supervise W 202 1 xvda1 10 40 0.56 |
| 1873 supervise W 202 1 xvda1 10 40 0.79 |
| 1871 supervise W 202 1 xvda1 10 40 0.78 |
| 1876 supervise W 202 1 xvda1 10 40 0.68 |
| 1892 supervise W 202 1 xvda1 10 40 0.71 |
| 1878 supervise W 202 1 xvda1 10 40 0.65 |
| 1886 supervise W 202 1 xvda1 10 40 0.78 |
| 1894 supervise W 202 1 xvda1 10 40 0.80 |
| 1869 supervise W 202 1 xvda1 10 40 0.91 |
| 1888 supervise W 202 1 xvda1 10 40 0.63 |
| 22069 bash R 202 1 xvda1 1 16 19.94 |
| 9251 kworker/u16:2 W 202 16 xvdb 2 8 0.13 |
| |
| 08:09:49 loadavg: 0.47 0.44 0.39 1/282 22231 |
| |
| PID COMM D MAJ MIN DISK I/O Kbytes AVGms |
| 22069 dd R 202 1 xvda1 13450 107600 0.35 |
| 22199 cksum R 202 1 xvda1 941 45548 4.63 |
| 326 jbd2/xvda1-8 W 202 1 xvda1 3 168 2.93 |
| 24467 kworker/0:2 W 202 16 xvdb 1 64 0.28 |
| 1880 supervise W 202 1 xvda1 10 40 0.81 |
| 1873 supervise W 202 1 xvda1 10 40 0.81 |
| 1871 supervise W 202 1 xvda1 10 40 1.03 |
| 1876 supervise W 202 1 xvda1 10 40 0.76 |
| 1892 supervise W 202 1 xvda1 10 40 0.74 |
| 1878 supervise W 202 1 xvda1 10 40 0.94 |
| 1886 supervise W 202 1 xvda1 10 40 0.76 |
| 1894 supervise W 202 1 xvda1 10 40 0.69 |
| 1869 supervise W 202 1 xvda1 10 40 0.72 |
| 1888 supervise W 202 1 xvda1 10 40 1.70 |
| 22199 bash R 202 1 xvda1 2 20 0.35 |
| 482 xfsaild/md0 W 202 16 xvdb 5 13 0.27 |
| 482 xfsaild/md0 W 202 32 xvdc 2 8 0.33 |
| 31331 pickup R 202 1 xvda1 1 4 0.31 |
| |
| 08:09:54 loadavg: 0.51 0.45 0.39 2/282 22346 |
| |
| PID COMM D MAJ MIN DISK I/O Kbytes AVGms |
| 22069 dd R 202 1 xvda1 14689 117512 0.32 |
| 326 jbd2/xvda1-8 W 202 1 xvda1 3 168 2.33 |
| 1880 supervise W 202 1 xvda1 10 40 0.65 |
| 1873 supervise W 202 1 xvda1 10 40 1.08 |
| 1871 supervise W 202 1 xvda1 10 40 0.66 |
| 1876 supervise W 202 1 xvda1 10 40 0.79 |
| 1892 supervise W 202 1 xvda1 10 40 0.67 |
| 1878 supervise W 202 1 xvda1 10 40 0.66 |
| 1886 supervise W 202 1 xvda1 10 40 1.02 |
| 1894 supervise W 202 1 xvda1 10 40 0.88 |
| 1869 supervise W 202 1 xvda1 10 40 0.89 |
| 1888 supervise W 202 1 xvda1 10 40 1.25 |
| |
| 08:09:59 loadavg: 0.55 0.46 0.40 2/282 22461 |
| |
| PID COMM D MAJ MIN DISK I/O Kbytes AVGms |
| 22069 dd R 202 1 xvda1 14442 115536 0.33 |
| 326 jbd2/xvda1-8 W 202 1 xvda1 3 168 3.46 |
| 1880 supervise W 202 1 xvda1 10 40 0.87 |
| 1873 supervise W 202 1 xvda1 10 40 0.87 |
| 1871 supervise W 202 1 xvda1 10 40 0.78 |
| 1876 supervise W 202 1 xvda1 10 40 0.86 |
| 1892 supervise W 202 1 xvda1 10 40 0.89 |
| 1878 supervise W 202 1 xvda1 10 40 0.87 |
| 1886 supervise W 202 1 xvda1 10 40 0.86 |
| 1894 supervise W 202 1 xvda1 10 40 1.06 |
| 1869 supervise W 202 1 xvda1 10 40 1.12 |
| 1888 supervise W 202 1 xvda1 10 40 0.98 |
| |
| 08:10:04 loadavg: 0.59 0.47 0.40 3/282 22576 |
| |
| PID COMM D MAJ MIN DISK I/O Kbytes AVGms |
| 22069 dd R 202 1 xvda1 14179 113432 0.34 |
| 326 jbd2/xvda1-8 W 202 1 xvda1 3 168 2.39 |
| 1880 supervise W 202 1 xvda1 10 40 0.81 |
| 1873 supervise W 202 1 xvda1 10 40 1.02 |
| 1871 supervise W 202 1 xvda1 10 40 1.15 |
| 1876 supervise W 202 1 xvda1 10 40 1.10 |
| 1892 supervise W 202 1 xvda1 10 40 0.77 |
| 1878 supervise W 202 1 xvda1 10 40 0.72 |
| 1886 supervise W 202 1 xvda1 10 40 0.81 |
| 1894 supervise W 202 1 xvda1 10 40 0.86 |
| 1869 supervise W 202 1 xvda1 10 40 0.83 |
| 1888 supervise W 202 1 xvda1 10 40 0.79 |
| 24467 kworker/0:2 R 202 32 xvdc 3 12 0.26 |
| 1056 cron R 202 1 xvda1 2 8 0.30 |
| 24467 kworker/0:2 R 202 16 xvdb 1 4 0.23 |
| |
| 08:10:09 loadavg: 0.54 0.46 0.40 2/281 22668 |
| |
| PID COMM D MAJ MIN DISK I/O Kbytes AVGms |
| 22069 dd R 202 1 xvda1 250 2000 0.34 |
| 326 jbd2/xvda1-8 W 202 1 xvda1 3 168 2.40 |
| 1880 supervise W 202 1 xvda1 8 32 0.93 |
| 1873 supervise W 202 1 xvda1 8 32 0.76 |
| 1871 supervise W 202 1 xvda1 8 32 0.60 |
| 1876 supervise W 202 1 xvda1 8 32 0.61 |
| 1892 supervise W 202 1 xvda1 8 32 0.68 |
| 1878 supervise W 202 1 xvda1 8 32 0.90 |
| 1886 supervise W 202 1 xvda1 8 32 0.57 |
| 1894 supervise W 202 1 xvda1 8 32 0.97 |
| 1869 supervise W 202 1 xvda1 8 32 0.69 |
| 1888 supervise W 202 1 xvda1 8 32 0.67 |
| |
| This shows another "dd" command reading from xvda1. On this system, various |
| "supervise" processes do 8 disk writes per second, every second (they are |
| creating and updating "status" files). |
| |
| |
| USAGE message: |
| |
| # ./biotop.py -h |
| usage: biotop.py [-h] [-C] [-r MAXROWS] [interval] [count] |
| |
| Block device (disk) I/O by process |
| |
| positional arguments: |
| interval output interval, in seconds |
| count number of outputs |
| |
| optional arguments: |
| -h, --help show this help message and exit |
| -C, --noclear don't clear the screen |
| -r MAXROWS, --maxrows MAXROWS |
| maximum rows to print, default 20 |
| |
| examples: |
| ./biotop # block device I/O top, 1 second refresh |
| ./biotop -C # don't clear the screen |
| ./biotop 5 # 5 second summaries |
| ./biotop 5 10 # 5 second summaries, 10 times only |
