Memory Manager Statistics

R←{X}(2000⌶)Y

This function returns information about the state of the workspace and provides a means to reset certain statistics and to control workspace allocation. This I-Beam is provided for performance tuning and is VERY LIKELY to change in the next release. See also Workspace Management.

Y is a simple integer scalar or vector containing values listed in the table below.

If X is omitted, the result R is an array with the same structure as Y, but with values in Y replaced by the following statistics. For any value in Y outside those listed below, the result is undefined.

Value	Description
0	Workspace available (a "quick" ⎕WA)
1	Workspace used
2	Number of compactions since the workspace was loaded
3	Number of garbage collections that found garbage
4	Current number of garbage pockets in the workspace
9	Current number of free pockets in the workspace
10	Current number of used pockets in the workspace
12	Sediment size
13	Current workspace allocation, i.e. the amount of memory that is actually being used
14	Workspace allocation high-water mark, i.e. the maximum amount of memory that has been allocated since the workspace was loaded or since this count was reset.
15	Limit on minimum workspace allocation
16	Limit on maximum workspace allocation
19	The number of calls to ⎕WA or 2002⌶ since the last time 2000⌶ was called, or when the process started.

Note that while all other operations are relatively fast, the operation to count the number of garbage pockets (4) may take a noticeable amount of time, depending upon the size and state of the workspace.

Examples

      2000⌶0
55414796
      2000⌶0,⍳16   ⍝ with MAXWS=95G
1.02004292E11 1181312 1 1 0 ¯1 ¯1 ¯1 ¯1 78 13280 ¯1 1180800 1595016496 1595042464 0 1.020054733E11

If X is specified, it must be either a simple integer scalar, or a vector of the same length as Y, and the result R is ⍬. In this case, the value in Y specifies the item to be set and X specifies its new value according to the table below.

Value	Description
2	0 resets the compaction count; no other values allowed
3	0 resets the count of garbage collections that found garbage; no other values allowed
14	0 resets the workspace allocation high-water mark; no other values allowed. This should be called following a call to ⎕WA (which compacts the workspace and returns unused memory to the operating system).
15	Sets the minimum workspace allocation to the corresponding value in X; must be between 0 and the current workspace allocation
16	Sets the maximum workspace allocation to the corresponding value in X; 0 implies MAXWS otherwise must be between the current workspace allocation and MAXWS.
19	0 resets the compaction count; no other values allowed

Notes:

Note that the workspace allocation high-water mark indicates a minimum value for MAXWS.
Limiting the maximum workspace allocation can be used to prevent code which grabs as much workspace as it can from skewing the peak usage result.
Limiting the minimum workspace allocation can avoid repeatedly committing and releasing memory to the Operating System when memory usage is fluctuating.

Examples

      2000⌶2 3
6 0 33216252
      0 (2000⌶)2 3 14 ⍝ Reset compaction count

      2000⌶2 3
0 0
      30000000 40000000(2000⌶)15 16 ⍝ Restrict min/max ws

      (2000⌶)15 16
30000000 40000000

      0 (2000⌶)15 16 ⍝ Reset min/max ws

      (2000⌶)15 16
0 65536000

      (2000⌶)13 14 ⍝ Current, peak WS allocation
4072532 4072532

      a←10e6⍴'x' ⍝ Increase WS allocation

      (2000⌶)13 14 ⍝ Current, peak WS allocation
15108580 15108580

      ⎕ex 'a' ⋄ {}⎕wa ⍝ Decrease current WS allocation

      (2000⌶)13 14 ⍝ Current, peak WS allocation
1962856 15108580

      0 (2000⌶) 14 ⍝ Reset High-water mark

      (2000⌶)13 14 ⍝ Current, peak WS allocation
1962856 1962856