When displaying aggregated data, you can sort the output. The output can be sorted based on aggregation keys or aggregation variables. The following options are available to sort the output:
Sort aggregation by key order with ties broken by value.
Position of the aggregate key on which the output is sorted.
Position of the argument in the aggregate function on which the output is sorted.
Sort aggregation in the reverse order.
For example, consider the following aggsort.d script that prints aggregation values.
/* aggsort.d */
syscall::read:entry
{
@avg[execname, pid] = avg(arg2);
@max[execname, pid] = max(arg2);
@min[execname, pid] = min(arg2);
@cnt[execname, pid] = count();
}
END
{
printf("%20s %10s %10s %10s %10s %10s\n", "EXECNAME", "PID", "COUNT", "MIN", "MAX", "AVG");
printa("%20s %10d %@10d %@10d %@10d %@10d\n", @cnt, @min, @max, @avg);
}
Running the aggsort.d script displays an output similar to the following:
# dtrace -q -s ./aggsort.d ^C EXECNAME PID COUNT MIN MAX AVG battstat-applet- 100981 2 32 32 32 gnome-settings-d 100853 3 32 64 53 soffice.bin 101382 10 32 32 32 dsdm 100708 10 32 160 54 xscreensaver 101082 14 32 32 32 gnome-panel 100896 24 12 168 51 firefox-bin 101363 31 1 1024 35 gnome-terminal 101029 40 32 4096 163 nautilus 100906 119 32 480 48 wnck-applet 100961 161 8 128 32 metacity 100893 447 4 96 33 Xorg 100534 926 64 5104 3263
If you want to sort the output based on the pid which is the second aggregation key, you must specify the aggsortkey and the aggsortkeypos options. Running the aggsort.d with these options, displays an output similar to the following:
# dtrace -q -s ./aggsort.d -x aggsortkey -x aggsortkeypos=1 ^C EXECNAME PID COUNT MIN MAX AVG Xorg 100534 885 64 4940 3688 dsdm 100708 23 32 128 40 gnome-settings-d 100853 4 32 64 40 metacity 100893 196 4 128 34 gnome-panel 100896 26 12 168 49 nautilus 100906 79 32 320 40 wnck-applet 100961 161 8 96 32 gnome-terminal 101029 27 32 4096 220 xscreensaver 101082 11 32 64 34 thunderbird-bin 101337 2 1 1024 512 firefox-bin 101363 29 1 1024 36 soffice.bin 101382 525 4 1440 33
To sort the output based on any of the aggregation variables, you must use the aggsortpos option. Running the following command sorts the output based on MAX which is the third aggregation variable.
# dtrace -q -s ./aggsort.d -x aggsortpos=2
To sort the aggregation values in a reverse order, use the aggsortrev option. For example:
# dtrace -q -s ./aggsort.d -x aggsortrev