sort a foreach on a stat value?

["Stone, Joshua I" <joshua dot i dot stone at intel dot com>]

Do we have a syntax to sort a foreach based on a stat value?  Obviously
this doesn't make sense for a histogram, but for the others, like
@count, it seems that this would very often be what a user would want to
do.

For example - here's an unscalable way to do simple thread profiling:

global stat
probe my.event { ++stat[tid()] }
probe end {
  foreach(tid in stat-) // sort by value -> most active
    printf("%d: %d\n", tid, stat[tid])
}

The scalable, per-cpu way to do this is:

global stat
probe my.event { stat[tid()]<<<1 }
probe end {
  foreach(tid in stat-) // sort by value -> ???
    printf("%d: %d\n", tid, @count(stat[tid]))
}

But there doesn't seem to be a way to achieve the same sorting.

Along the same lines, it would be extremely useful to be able to do
"cascading" sort - i.e. sort by more than one field.


Josh