[gclist] Re: Name that hypothesis
Wed, 4 Dec 1996 16:25:05 +0100
|| From: Nick Barnes <email@example.com>
|| Date: Tue, 03 Dec 1996 12:40:38 +0000
|| Subject: [gclist] Name that hypothesis
|| What is the name of the following hypothesis?
|| "Most references in a system point backwards in time, i.e. from
|| younger objects to older objects."
We tested that hypothesis. It is incorrect.
Specifically, here is how some well-known C programs behave:
- cfrac: most are forward (in time) but a large proportion are backward
- gs: almost all are backward
- espresso: almost all are forward
- ical: equally balanced, forward and backward
- gawk: a high peak of backward pointers, but a long tail of forward ones
- GNU make: equally balanced in both directions
- perl: mostly backwards
The above is for live objects. Interestingly the behaviour differs for
- cfrac: results not significant
- gs: backwards
- espresso: equal balance
- ical: most backwards
- gawk: high peak backwards, long tail forwards
- GNU make: backwards
- perl: predominantly backwards
The exact figures can be found in the master's thesis of one of my students:
Mesure et caractérisation d'applications réparties
See Figure 4.12 and 4.10.
M. Shapiro, INRIA Rocquencourt, BP 105, 78153 Le Chesnay Cedex, France.
Tel.: +33 1 39 63 53 25. Fax: +33 1 39 63 53 30.
e-mail: firstname.lastname@example.org. http://www-sor.inria.fr/~shapiro/