HP PAK Performance Analysis Tools User's Guide

24 Chapter 2

Puma Concepts

How Puma Analyzes Recursive Procedures

stub built at the recursive call to a, since the transformation from main

a b a to main a loses the only instance of b. However, it would have a

recursive stub at the recursive call to b, since the collapsing of main a b

a b to main a b loses an instance of a, but leaves another one. As

another example, the call chain main a b c b a d c would not have

any recursive stubs using Conservative collapse. Building a stub at

the recursive second call to b would lose c; building one at the recursive

second call to a would lose b and c; and building one at the recursive

second call to c would lose d.

Full Collapse

The Full collapse option causes a recursive stub to be built whenever

there is any higher instance of a routine in the call tree. For example, for

main a b c b a d c, the call chain that is discussed above, a stub

would be created from the recursive call to b, and another at the

recursive call to a. There would not be one at the recursive call to c,

because after the other recursive jumps the other instance of c is no

longer higher in the tree. In particular, the analysis just from this one

stack trace would look like the following example.

Samples Samples

In or Under In Only

Raw Count Raw Count Level

---

1 0 1 main

102a

103b

104c

5 b...

4 a...

0 (1) 0 3 d

0 (1) 1 4 c

When Puma encounters the second b in the call chain main a b c

b a d c, it builds a recursive stub (at Level 5 in the analysis) up to the

higher b (at Level 3). It then jumps up to that b. When it comes to the

second a, Puma builds a recursive stub (the a at Level 4) as a child of the

instance of b at Level 3, and pointing up to the instance of a at Level 2.

For d, Puma builds an ordinary node (not a recursive stub). For the ﬁnal

c (the last line of the analysis), it does not build a recursive stub, because

the ﬁrst c is not an ancestor of the current node. The ancestors of the

current node are d , a (at Level 2), and main (at Level 1). The last two