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Diffstat (limited to 'Examples/sh_wasted_example.txt')
-rw-r--r-- | Examples/sh_wasted_example.txt | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/Examples/sh_wasted_example.txt b/Examples/sh_wasted_example.txt new file mode 100644 index 000000000000..b11f9523db39 --- /dev/null +++ b/Examples/sh_wasted_example.txt @@ -0,0 +1,45 @@ +Many shell programmers are in the habit of using calls to external commands +instead of using shell built-in commands (an example of this is a call to +usr/bin/echo instead of using the echo command built into the shell. + +This script shows sh_wasted.d tracing a shell script that calls /usr/bin/echo +instead of using the built-in. + +# sh_wasted.d -c ./func_waste.sh +Tracing... Hit Ctrl-C to end. +Function A +Function B +Function C +Script duration: 3101631 us + +External command elapsed times, + FILE NAME TIME(us) + func_waste.sh sleep 3019573 + +Wasted command elapsed times, + FILE NAME TIME(us) + func_waste.sh /usr/bin/echo 26510 + +You can see that the calls to /usr/bin/echo took around 26 thousand +microseconds; time wasted by the shell having to access an external command. + + +Here we trace the same script, except it uses the shell built-in echo command. + +# sh_wasted.d -c ./func_abc.sh +Function A +Tracing... Hit Ctrl-C to end. +Function B +Function C +Script duration: 3032616 us + +External command elapsed times, + FILE NAME TIME(us) + func_abc.sh sleep 3012920 + +Wasted command elapsed times, + FILE NAME TIME(us) + +The total time here is less and there are no 'wasted' calls to external +commands. + |