Add TotalMemoryAllocated() and memory_allocated.

These are analogs of Runtime() and time, but for allocated memory.
gap-system · Oct 31, 2017 · 80b7532 · 80b7532
1 parent 2be5f06
commit 80b7532
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Showing 3 changed files with 65 additions and 7 deletions.
diff --git a/doc/ref/debug.xml b/doc/ref/debug.xml
@@ -423,11 +423,14 @@ should be treated as an estimate.
 </ManSection>
 
 <ManSection>
-<Var Name="time"/>
+  <Var Name="time"/>
+  <Var Name="memory_allocated"/>
 
 <Description>
 In the read-eval-print loop,
-<Ref Var="time"/> stores the number of milliseconds the last command took.
+<Ref Var="time"/> stores the number of milliseconds the last command
+took. and <Ref Var="memory_allocated"/> stored the number of bytes of
+memory it allocated.
 </Description>
 </ManSection>
 
@@ -444,6 +447,27 @@ in nanoseconds.
 
 </Section>
 
+<!-- %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% -->
+<Section Label="Tracking Memory Usage">
+  <Heading>Tracking Memory Usage</Heading>
+
+  <ManSection>
+    <Func Name="TotalMemoryAllocated" Arg=""/>
+    <Description> <Ref Func="TotalMemoryAllocated"/> returns the total amount of memory
+    in bytes allocated by the &GAP; memory manager since &GAP; started.
+    </Description>
+  </ManSection>
+  <ManSection>
+  <Var Name="memory_allocated"/>
+
+<Description>
+In the read-eval-print loop,
+<Ref Var="memory_allocated"/> stores the number of bytes of
+memoryallocated by the last completed statement.
+</Description>
+</ManSection>
+
+</Section>
 
 <!-- %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% -->
 <Section Label="Profiling">

diff --git a/doc/ref/mloop.xml b/doc/ref/mloop.xml
@@ -27,6 +27,8 @@ interactive environment in which you use &GAP;.
 <Index Key="last"><C>last</C></Index>
 <Index Key="last2"><C>last2</C></Index>
 <Index Key="last3"><C>last3</C></Index>
+<Index Key="time"><C>time</C></Index>
+<Index Key="memory_allocated"><C>memory_allocated</C></Index>
 <Index>previous result</Index>
 The normal interaction with &GAP; happens in the so-called
 <E>read-eval-print</E> loop.
@@ -154,8 +156,10 @@ gap> last3 + last2 * last;
 ]]></Example>
 <P/>
 Also in each statement the time spent by the last statement, whether it
-produced a value or not, is available in the variable <Ref Var="time"/>.
-This is an integer that holds the number of milliseconds.
+produced a value or not, is available in the variable <Ref
+Var="time"/>. This is an integer that holds the number of
+milliseconds. Similarly the amount of memory allocated during that
+statement (in bytes) is stored in the variable <Ref Var="memory_allocated"/>.
 
 </Section>
 

diff --git a/src/gap.c b/src/gap.c
@@ -148,6 +148,16 @@ UInt Last3;
 */
 UInt Time;
 
+/****************************************************************************
+**
+*V  MemoryAllocated. . . . . . . . . . .  global variable  'memory_allocated'
+**
+**  'MemoryAllocated' is the global variable 'memory_allocated', 
+**  which is automatically assigned the amount of memory allocated while
+**  executing the last command.
+*/
+UInt MemoryAllocated;
+
 
 /****************************************************************************
 **
@@ -226,6 +236,7 @@ Obj Shell ( Obj context,
             Char *outFile)
 {
   UInt time = 0;
+  UInt mem = 0;
   UInt status;
   Obj evalResult;
   UInt dualSemicolon;
@@ -261,8 +272,10 @@ Obj Shell ( Obj context,
   while ( 1 ) {
 
     /* start the stopwatch                                             */
-    if (setTime)
-      time = SyTime();
+    if (setTime) {
+          time = SyTime();
+          mem = SizeAllBags;
+    }
 
     /* read and evaluate one command                                   */
     STATE(Prompt) = prompt;
@@ -339,8 +352,14 @@ Obj Shell ( Obj context,
     }
 
     /* stop the stopwatch                                          */
-    if (setTime)
+    if (setTime) {
       AssGVar( Time, INTOBJ_INT( SyTime() - time ) );
+      /* This should be correct for small allocated totals at least, 
+         even on 32 bits, but this functionality will never be very useful
+         on 32 bits */         
+      AssGVar(MemoryAllocated,
+              INTOBJ_INT((SizeAllBags - mem) % (1L << NR_SMALL_INT_BITS)));
+    }
 
     if (STATE(UserHasQuit))
       {
@@ -1944,6 +1963,14 @@ Obj FuncSHALLOW_SIZE (
     return ObjInt_UInt( SIZE_BAG( obj ) );
 }
 
+/****************************************************************************
+**
+*F  FuncTotalMemoryAllocated( <self> ) .expert function 'TotalMemoryAllocated'
+*/
+
+Obj FuncTotalMemoryAllocated( Obj self ) {
+    return INTOBJ_INT(SizeAllBags);
+}
 
 /****************************************************************************
 **
@@ -2871,6 +2898,7 @@ static StructGVarFunc GVarFuncs [] = {
     GVAR_FUNC(GASMAN_MESSAGE_STATUS, 0, ""),
     GVAR_FUNC(GASMAN_LIMITS, 0, ""),
     GVAR_FUNC(SHALLOW_SIZE, 1, "object"),
+    GVAR_FUNC(TotalMemoryAllocated, 0, ""),
     GVAR_FUNC(TNUM_OBJ, 1, "object"),
     GVAR_FUNC(TNUM_OBJ_INT, 1, "object"),
     GVAR_FUNC(OBJ_HANDLE, 1, "object"),
@@ -2969,7 +2997,9 @@ static Int PostRestore (
     Last2             = GVarName( "last2" );
     Last3             = GVarName( "last3" );
     Time              = GVarName( "time"  );
+    MemoryAllocated   = GVarName( "memory_allocated"  );
     AssGVar(Time, INTOBJ_INT(0));
+    AssGVar(MemoryAllocated, INTOBJ_INT(0));
     QUITTINGGVar      = GVarName( "QUITTING" );
 
     /* return success                                                      */