Features/PowerManagement/scomes

Please see Features/PowerManagement for more.

= scomes =

Scomes is a SystemTap script to watch resources consumed by the program. Now it is part of the tuned project (tuned-utils package).

Goal:


 * Measure amount of system resources consumed by the program.
 * Use these data to compare different programming techniques in view of system resources.
 * Create programming tips based on these results.

How it works: using systemtap - http://sources.redhat.com/systemtap/wiki/ script watches given binary for syscalls, kernel and userspace ticks, read and written bytes, transmitted bytes and polling syscalls, and enumerates score from these values.

scomes is part of tuned-utils package.

Usage
Prepare your system:


 * 1) yum install systemtap tuned-utils
 * 2) debuginfo-install kernel

Run scomes.stp
Binary you want to measure should be named uniquely (or ensure there are no other binaries with same name running on the system).

Now run the scomes with the command-line option being name of the binary and then run the binary:


 * 1) scomes.stp -c " [ ...]"   # wait untill it starts
 * binary [binary args ...]
 * measured program


 * timer
 * how often you want to see current results, value is in seconds and 0 means "show only last results"

scomes will start to output statistics each seconds and once binary ends, it will output final statistic like this:

Collecting data... --- Monitored execname: sleep Number of syscalls: 59 Kernel/Userspace ticks: 3/1 (4) Read/Written bytes: 3620/0 (3620) Transmitted/Recived bytes: 0/0 (0) Pooling syscalls: 0 SCORE: 36205 --- Monitored execname: sleep Number of syscalls: 59 Kernel/Userspace ticks: 3/1 (4) Read/Written bytes: 3620/0 (3620) Transmitted/Recived bytes: 0/0 (0) Pooling syscalls: 0 SCORE: 36205 --- LAST RESULTS: --- Monitored execname: sleep Number of syscalls: 63 Kernel/Userspace ticks: 4/1 (5) Read/Written bytes: 3620/0 (3620) Transmitted/Recived bytes: 0/0 (0) Pooling syscalls: 1 SCORE: 36206 --- QUITTING ---
 * 1) ./scomes.stp -c "/bin/sleep 4" 2

Note: on F11 please call scomes with `stap --skip-badvars scomes.stp`.

Explain statistics

 * Monitored execname
 * name of the binary (passed as a command-line argument)


 * Number of syscalls
 * number of all syscalls performed by the binary


 * Kernel/Userspace ticks
 * count of the processor ticks binary uses in the kernel or in userspace respectively (`kticks` and `uticks` variables)


 * Read/Written bytes
 * sum of the read and written bytes from the file binary does (`reads, writes` variables)


 * Transmitted/Recived bytes
 * sum of the read and written bytes from the network binary does (`ifxmit` and `ifrecv` variables)


 * Polling syscalls
 * "bad" polling syscals binary does (poll, select, epoll, itimer, futex, nanosleep, signal)


 * SCORE
 * TODO - but for now: `SCORE = kticks + 2*uticks + 10*(reads+writes) + ifxmit + ifrecv`

First examples
http://fedoraproject.org/wiki/Features/PowerManagement/scomes/examples

normal:
Monitored execname: sleep Number of syscalls: 33 Kernel/Userspace ticks: 2/0 Read/Written bytes: 736 Transmitted/Recived bytes: 0 Pooling syscalls: 1 SCORE: 7362

busybox - statically linked:
Monitored execname: busybox Number of syscalls: 7 Kernel/Userspace ticks: 1/0 Read/Written bytes: 0 Transmitted/Recived bytes: 0 Pooling syscalls: 1 SCORE: 1

busybox.anaconda - dynamically linked:
Monitored execname: sleep Number of syscalls: 39 Kernel/Userspace ticks: 0/2 Read/Written bytes: 1248 Transmitted/Recived bytes: 0 Pooling syscalls: 0 SCORE: 12484