Data Returned by Memstats

The vector returned from memstats has the content as shown below, ordered by increasing index. Note that this vector is not laid out in the same way as the data produced by stats-dump-on.

THIS IS NO LONGER CORRECT. SEE Lib/Common/memstats.sch FOR THE LIST OF ACCESSOR FUNCTIONS TO MANIPULATE THE STRUCTURE RETURNED FROM MEMSTATS. THE DOCUMENTATION WILL BE UPDATED AT SOME POINT.

0. Number of words allocated (accumulated)
1. Number of words reclaimed (accumulated)
2. Number of words copied (accumulated)
3. Milliseconds spent in garbage collection (accumulated, including promotion). See also entry 28.
4. Words live (current)
5. Generation last collected (current)
6. Type of last collection: 0=collection, 1=promotion (current)
7. Generation information: a vector of vectors, one subvector for each generation, containing the following:

7.0. Number of garbage collections in generation (accumulated)
7.1. Number of promotions into generation (accumulated)
7.2. Time spent in the generation's garbage collector for collections and promotions (accumulated)
7.3. Words live in the generation (current)
7.4. Flag: this is a non-predictive 'young' generation (0 or 1)
7.5. Flag: this is a non-predictive 'old' generation (0 or 1)
7.6. If a non-predictive generation, the value 'j'
7.7. If a non-predictive generation, the value 'k'
7.8. Words allocated to the generation (current). Note that this is the sum of the allocations for both semispaces, if there are semispaces. Therefore, allocation can exceed target size.
7.9. The generation's target size, in words (current). Note that this is per semispace.
7.10. Time spent promoting into the generation (accumulated).
8. Remembered-set information: a vector of vectors, one subvector for each remembered set, containing the following:
8.0. Words allocated to remembered set node pool (current)
8.1. Words used in remembered set node pool (current)
8.2. Words allocated to remembered set hash table (current)
8.3. Words used in remembered set hash table (current)
8.4. Number of objects recorded in hash table (accumulated)
8.5. Number of objects removed from hash table (accumulated)
8.6. Number of old-generation objects scanned from remembered set (accumulated)
8.7. Number of words of old-generation objects scanned from remembered set (accumulated)
8.8. Number of transactions recorded in the remembered set's sequential store buffer (SSB)
9. Number of stack frames flushed (accumulated)
10. Number of words of stack flushed (accumulated)
11. Number of stacks created (accumulated)
12. Number of stack frames restored (accumulated)
13. Number of words allocated to heaps (current)
14. Number of words allocated to remembered-sets (current)
15. Number of words allocated to RTS "other" (current)
16. Simulated write barrier: number of array assignments (accumulated)
17. Simulated write barrier: number of array assignments filtered because the LHS is young or already remembered (accumulated)
18. Simulated write barrier: number of array assignments filtered because the RHS is a non-pointer (accumulated)
19. Simulated write barrier: number of array assignments filtered because a cross-generation pointer was not created
20. Simulated write barrier: number of array assignments that resulted in the LHS being added to a remembered set
21. Elapsed time since startup.
22. System CPU time since startup.
23. User CPU time since startup.
24. Number of page faults that did not incur a physical read ("minor") (accumulated)
25. Number of page faults that did inclur a physical read ("major") (accumulated)
26. Remembered-set statistics for the extra remembered set for the non-predictive collector, or #f
27. Number of words of maximum heap occupancy so far during the run.
28. Milliseconds spent in promotion.

$Id: memstats.html,v 1.3 2000/02/29 20:55:29 lth Exp $
larceny@ccs.neu.edu