Remove SyCacheSize and the "-c" command line option

This code was meant as an optimization for CPUs with data cache (i.e. nowadays every CPU), but in practice it seems to have no noticeable impact. Resolves #273
gap-system · Apr 8, 2017 · d90ec2f · d90ec2f
1 parent e61903b
commit d90ec2f
Show file tree

Hide file tree

Showing 11 changed files with 16 additions and 142 deletions.
diff --git a/hpcgap/lib/system.g b/hpcgap/lib/system.g
@@ -76,7 +76,6 @@ BIND_GLOBAL( "GAPInfo", AtomicRecord(rec(
            help := [ "set hint for maximal workspace size (GAP may", "allocate more)"] ),
       rec( short:= "K", long := "limitworkspace", default := "0", arg := "<mem>",
            help := [ "set maximal workspace size (GAP never", "allocates more)"] ),
-      rec( short:= "c", default := "0", arg := "<mem>", help := [ "set the cache size value"] ),
       rec( short:= "s", default := "4g", arg := "<mem", help := [ "set the initially mapped virtual memory" ] ),
       rec( short:= "a", default := "0",  arg := "<mem>",help := [ "set amount to pre-malloc-ate",
              "postfix 'k' = *1024, 'm' = *1024*1024,", "'g' = *1024*1024*1024"] ),

diff --git a/hpcgap/src/gap.c b/hpcgap/src/gap.c
@@ -3367,7 +3367,7 @@ void InitializeGap (
     /* Initialise memory  -- have to do this here to make sure we are at top of C stack */
     InitBags( SyAllocBags, SyStorMin,
               0, (Bag*)(((UInt)pargc/SyStackAlign)*SyStackAlign), SyStackAlign,
-              SyCacheSize, 0, SyAbortBags );
+              0, SyAbortBags );
               InitMsgsFuncBags( SyMsgsBags ); 
 
     TLS(StackNams)    = NEW_PLIST( T_PLIST, 16 );

diff --git a/hpcgap/src/system.c b/hpcgap/src/system.c
@@ -116,22 +116,6 @@ const Char * SyArchitecture = SYS_ARCH;
 UInt SyCTRD;
 
 
-/****************************************************************************
-**
-*V  SyCacheSize . . . . . . . . . . . . . . . . . . . . . . size of the cache
-**
-**  'SyCacheSize' is the size of the data cache.
-**
-**  This is per  default 0, which means that  there is no usuable data cache.
-**  It is usually changed with the '-c' option in the script that starts GAP.
-**
-**  This value is passed to 'InitBags'.
-**
-**  Put in this package because the command line processing takes place here.
-*/
-UInt SyCacheSize;
-
-
 /****************************************************************************
 **
 *V  SyCheckCRCCompiledModule  . . .  check crc while loading compiled modules
@@ -1864,8 +1848,6 @@ struct optInfo options[] = {
   { 'R', "", unsetString, &SyRestoring, 0}, /* kernel */
   { 'U', "", storeString, SyCompileOptions, 1}, /* kernel */
   { 'a', "", storeMemory, &preAllocAmount, 1 }, /* kernel -- is this still useful */
-  { 'c', "", storeMemory, &SyCacheSize, 1 }, /* kernel, unless we provided a hook to set it from library, 
-                                           never seems to be useful */
   { 'e', "", toggle, &SyCTRD, 0 }, /* kernel */
   { 'f', "", forceLineEditing, (void *)2, 0 }, /* probably library now */
   { 'E', "", toggle, &SyUseReadline, 0 }, /* kernel */
@@ -1905,7 +1887,6 @@ void InitSystem (
     /* Initialize global and static variables. Do it here rather than
        with initializers to allow for restart */
     SyCTRD = 1;             
-    SyCacheSize = 0;
     SyCheckCRCCompiledModule = 0;
     SyCompilePlease = 0;
     SyDebugLoading = 0;

diff --git a/hpcgap/src/system.h b/hpcgap/src/system.h
@@ -203,22 +203,6 @@ extern const Char * SyBuildDateTime;
 extern UInt SyCTRD;
 
 
-/****************************************************************************
-**
-*V  SyCacheSize . . . . . . . . . . . . . . . . . . . . . . size of the cache
-**
-**  'SyCacheSize' is the size of the data cache, in kilobytes
-**
-**  This is per  default 0, which means that  there is no usuable data cache.
-**  It is usually changed with the '-c' option in the script that starts GAP.
-**
-**  This value is passed to 'InitBags'.
-**
-**  Put in this package because the command line processing takes place here.
-*/
-extern UInt SyCacheSize;
-
-
 /****************************************************************************
  **
  *V  SyCheckCRCCompiledModule  . . .  check crc while loading compiled modules

diff --git a/lib/system.g b/lib/system.g
@@ -75,7 +75,6 @@ BIND_GLOBAL( "GAPInfo", rec(
            help := [ "set hint for maximal workspace size (GAP may", "allocate more)"] ),
       rec( short:= "K", long := "limitworkspace", default := "0", arg := "<mem>",
            help := [ "set maximal workspace size (GAP never", "allocates more)"] ),
-      rec( short:= "c", default := "0", arg := "<mem>", help := [ "set the cache size value"] ),
       rec( short:= "s", default := "4g", arg := "<mem", help := [ "set the initially mapped virtual memory" ] ),
       rec( short:= "a", default := "0",  arg := "<mem>",help := [ "set amount to pre-malloc-ate",
              "postfix 'k' = *1024, 'm' = *1024*1024,", "'g' = *1024*1024*1024"] ),

diff --git a/src/gap.c b/src/gap.c
@@ -3273,7 +3273,7 @@ void InitializeGap (
     /* Initialise memory  -- have to do this here to make sure we are at top of C stack */
     InitBags( SyAllocBags, SyStorMin,
               0, (Bag*)(((UInt)pargc/SyStackAlign)*SyStackAlign), SyStackAlign,
-              SyCacheSize, 0, SyAbortBags );
+              0, SyAbortBags );
               InitMsgsFuncBags( SyMsgsBags ); 
 
     TLS(StackNams)    = NEW_PLIST( T_PLIST, 16 );

diff --git a/src/gasman.c b/src/gasman.c
@@ -270,19 +270,6 @@ TNumMarkFuncBags TabMarkFuncBags [ NTYPES ];
 **  allocation.   'StopBags'  points  to  the  beginning  of  this  area  and
 **  'EndBags' to the end.
 **
-**  If <cache-size>  (see "InitBags") was 0,  'CollectBags' makes all of  the
-**  free storage available for allocations by setting 'StopBags' to 'EndBags'
-**  after garbage collections.   In   this case garbage  collections are only
-**  performed when no  free storage   is left.  If <cache-size> was  nonzero,
-**  'CollectBags' makes 'AllocSizeBags' bytes available by setting 'StopBags'
-**  to  'AllocBags   + 2+WORDS_BAG(<size>) +  WORDS_BAG(AllocSizeBags)' after
-**  garbage  collections, where <size>   is the  size  of the bag 'NewBag' is
-**  currently allocating.  'AllocSizeBags'  is  usually <cache-size>,  but is
-**  increased if only very few large bags have been  allocated since the last
-**  garbage collection and decreased  again  if sufficiently many  bags  have
-**  been allocated since the  last  garbage collection.  The  idea is to keep
-**  the allocation area small enough so that it fits in the processor cache.
-**
 **  Note that  the  borders between the areas are not static.  In  particular
 **  each allocation increases the size of the young bags area and reduces the
 **  size of the  allocation area.  On the other hand each garbage  collection
@@ -950,7 +937,6 @@ void FinishedRestoringBags( void )
   SizeDeadBags = 0;
   NrHalfDeadBags = 0;
   ChangedBags = 0;
-  return;
 }
 
 
@@ -1016,7 +1002,7 @@ void FinishBags( void )
 *F  InitBags(...) . . . . . . . . . . . . . . . . . . . . . initialize Gasman
 **
 **  'InitBags'   remembers   <alloc-func>,  <stack-func>,     <stack-bottom>,
-**  <stack-align>, <cache-size>,  <dirty>,    and   <abort-func>  in   global
+**  <stack-align>, <dirty>,    and   <abort-func>  in   global
 **  variables.   It also  allocates  the initial workspace,   and sets up the
 **  linked list of available masterpointer.
 */
@@ -1028,8 +1014,6 @@ Bag *                   StackBottomBags;
 
 UInt                    StackAlignBags;
 
-UInt                    CacheSizeBags;
-
 UInt                    DirtyBags;
 
 TNumAbortFuncBags       AbortFuncBags;
@@ -1040,7 +1024,6 @@ void            InitBags (
     TNumStackFuncBags   stack_func,
     Bag *               stack_bottom,
     UInt                stack_align,
-    UInt                cache_size,
     UInt                dirty,
     TNumAbortFuncBags   abort_func )
 {
@@ -1080,17 +1063,8 @@ void            InitBags (
     YoungBags = OldBags;
     AllocBags = OldBags;
 
-    /* remember the cache size                                             */
-    CacheSizeBags = cache_size;
-    if ( ! CacheSizeBags ) {
-        AllocSizeBags = 256;
-        StopBags = EndBags;
-    }
-    else {
-        AllocSizeBags = (CacheSizeBags+1023)/1024;
-        StopBags  = AllocBags + WORDS_BAG(1024*AllocSizeBags) <= EndBags ?
-                    AllocBags + WORDS_BAG(1024*AllocSizeBags) :  EndBags;
-    }
+    AllocSizeBags = 256;
+    StopBags = EndBags;
 
     /* remember whether bags should be clean                               */
     DirtyBags = dirty;
@@ -2158,24 +2132,15 @@ UInt CollectBags (
     if ( ! FullBags ) {
 
         /* maybe adjust the size of the allocation area                    */
-        if ( ! CacheSizeBags ) {
-            if ( nrLiveBags+nrDeadBags +nrHalfDeadBags < 512
-
-                 /* The test below should stop AllocSizeBags
-                    growing uncontrollably when all bags are big */
-                 && StopBags > OldBags + 4*1024*WORDS_BAG(AllocSizeBags))
-                AllocSizeBags += 256L;
-            else if ( 4096 < nrLiveBags+nrDeadBags+nrHalfDeadBags
-                   && 256 < AllocSizeBags )
-                AllocSizeBags -= 256;
-        }
-        else {
-            if ( nrLiveBags+nrDeadBags < 512 )
-                AllocSizeBags += CacheSizeBags/1024;
-            else if ( 4096 < nrLiveBags+nrDeadBags+nrHalfDeadBags
-                   && CacheSizeBags < AllocSizeBags )
-                AllocSizeBags -= CacheSizeBags/1024;
-        }
+        if ( nrLiveBags+nrDeadBags +nrHalfDeadBags < 512
+
+             /* The test below should stop AllocSizeBags
+                growing uncontrollably when all bags are big */
+             && StopBags > OldBags + 4*1024*WORDS_BAG(AllocSizeBags))
+            AllocSizeBags += 256;
+        else if ( 4096 < nrLiveBags+nrDeadBags+nrHalfDeadBags
+               && 256 < AllocSizeBags )
+            AllocSizeBags -= 256;
 
         /* if we dont get enough free storage or masterpointers do full gc */
         if ( EndBags < StopBags + WORDS_BAG(1024*AllocSizeBags)
@@ -2297,10 +2262,7 @@ UInt CollectBags (
                          SpaceBetweenPointers(EndBags, MptrBags)/(1024/sizeof(Bag)));
 
     /* reset the stop pointer                                              */
-    if ( ! CacheSizeBags || EndBags < StopBags+WORDS_BAG(1024*AllocSizeBags) )
-        StopBags = EndBags;
-    else
-        StopBags = StopBags + WORDS_BAG(1024*AllocSizeBags);
+    StopBags = EndBags;
 
     /* if we are not done, then true again                                 */
     if ( ! done ) {

diff --git a/src/gasman.h b/src/gasman.h
@@ -1067,7 +1067,7 @@ extern void CheckMasterPointers( void );
 **
 **  InitBags( <alloc-func>, <initial-size>,
 **            <stack-func>, <stack-start>, <stack-align>,
-**            <cache-size>, <dirty>, <abort-func> )
+**            <dirty>, <abort-func> )
 **
 **  'InitBags'  initializes {\Gasman}.  It  must be called from a application
 **  using {\Gasman} before any bags can be allocated.
@@ -1128,20 +1128,6 @@ extern void CheckMasterPointers( void );
 **  on  the   machine,  the  operating system,   and   the compiler.   If the
 **  application provides another <stack-func>, <stack-align> is ignored.
 **
-**  <cache-size>  informs {\Gasman} whether  the  processor has a usable data
-**  cache and how large it is  measured in bytes.   If the application passes
-**  0, {\Gasman} assumes that the processor has no data cache or a data cache
-**  to small to be   useful.  In this case  the  entire free storage is  made
-**  available for allocations after garbage  collections.  If the application
-**  passes a  nonzero value, {\Gasman}  assumes that this is  the size of the
-**  part of the data cache that should  be used for  the allocation area, and
-**  tries  to keep the allocation  area small enough  so that it fits.  For a
-**  processor that has separate  data and instruction caches, the application
-**  should pass the size of the data cache minus 65536.  For a processor with
-**  a  unified cache,  the application  should  pass the size  of the unified
-**  cache minus   131072.  The application probably should   not pass a value
-**  less than 131072.
-**
 **  The initialization  flag  <dirty> determines  whether  bags allocated  by
 **  'NewBag' are initialized to contain only 0 or not.   If <dirty> is 0, the
 **  bags are  initialized to  contain only 0.    If  <dirty> is  1, the  bags
@@ -1169,7 +1155,6 @@ extern  void            InitBags (
             TNumStackFuncBags   stack_func,
             Bag *               stack_bottom,
             UInt                stack_align,
-            UInt                cache_size,
             UInt                dirty,
             TNumAbortFuncBags   abort_func );
 

diff --git a/src/hpc/boehm_gc.h b/src/hpc/boehm_gc.h
@@ -304,7 +304,6 @@ void            InitBags (
     TNumStackFuncBags   stack_func,
     Bag *               stack_bottom,
     UInt                stack_align,
-    UInt                cache_size,
     UInt                dirty,
     TNumAbortFuncBags   abort_func )
 {

diff --git a/src/system.c b/src/system.c
@@ -116,22 +116,6 @@ const Char * SyArchitecture = SYS_ARCH;
 UInt SyCTRD;
 
 
-/****************************************************************************
-**
-*V  SyCacheSize . . . . . . . . . . . . . . . . . . . . . . size of the cache
-**
-**  'SyCacheSize' is the size of the data cache.
-**
-**  This is per  default 0, which means that  there is no usuable data cache.
-**  It is usually changed with the '-c' option in the script that starts GAP.
-**
-**  This value is passed to 'InitBags'.
-**
-**  Put in this package because the command line processing takes place here.
-*/
-UInt SyCacheSize;
-
-
 /****************************************************************************
 **
 *V  SyCheckCRCCompiledModule  . . .  check crc while loading compiled modules
@@ -1809,8 +1793,6 @@ struct optInfo options[] = {
   { 'R', "", unsetString, &SyRestoring, 0}, /* kernel */
   { 'U', "", storeString, SyCompileOptions, 1}, /* kernel */
   { 'a', "", storeMemory, &preAllocAmount, 1 }, /* kernel -- is this still useful */
-  { 'c', "", storeMemory, &SyCacheSize, 1 }, /* kernel, unless we provided a hook to set it from library, 
-                                           never seems to be useful */
   { 'e', "", toggle, &SyCTRD, 0 }, /* kernel */
   { 'f', "", forceLineEditing, (void *)2, 0 }, /* probably library now */
   { 'E', "", toggle, &SyUseReadline, 0 }, /* kernel */
@@ -1845,7 +1827,6 @@ void InitSystem (
     /* Initialize global and static variables. Do it here rather than
        with initializers to allow for restart */
     SyCTRD = 1;             
-    SyCacheSize = 0;
     SyCheckCRCCompiledModule = 0;
     SyCompilePlease = 0;
     SyDebugLoading = 0;

diff --git a/src/system.h b/src/system.h
@@ -203,22 +203,6 @@ extern const Char * SyBuildDateTime;
 extern UInt SyCTRD;
 
 
-/****************************************************************************
-**
-*V  SyCacheSize . . . . . . . . . . . . . . . . . . . . . . size of the cache
-**
-**  'SyCacheSize' is the size of the data cache, in kilobytes
-**
-**  This is per  default 0, which means that  there is no usuable data cache.
-**  It is usually changed with the '-c' option in the script that starts GAP.
-**
-**  This value is passed to 'InitBags'.
-**
-**  Put in this package because the command line processing takes place here.
-*/
-extern UInt SyCacheSize;
-
-
 /****************************************************************************
  **
  *V  SyCheckCRCCompiledModule  . . .  check crc while loading compiled modules