gc tweaking to gain a few percent of performance

compiler/cgen.nim

@@ -677,8 +677,8 @@ proc genProcAux(m: BModule, prc: PSym) =
     if optStackTrace in prc.options: app(generatedProc, deinitFrame(p))
     if (optProfiler in prc.options) and (gCmd != cmdCompileToLLVM): 
       appf(generatedProc, 
-          "profileData[$1].total += elapsed(getticks(), NIM_profilingStart);$n", 
-           [toRope(prc.loc.a)])
+        "profileData[$1].total += elapsed(getticks(), NIM_profilingStart);$n", 
+        [toRope(prc.loc.a)])
     app(generatedProc, returnStmt)
     app(generatedProc, '}' & tnl)
   app(m.s[cfsProcs], generatedProc)

compiler/crc.nim

@@ -100,19 +100,16 @@ proc crcFromBuf(buf: Pointer, length: int): TCrc32 =
   
 proc crcFromFile(filename: string): TCrc32 = 
   const 
-    bufSize = 8 * 1024
+    bufSize = 8000 # don't use 8K for the memory allocator!
   var 
     bin: tfile
-    buf: Pointer
-    readBytes: int
-    p: PByteArray
   result = InitCrc32
   if not open(bin, filename): 
     return                    # not equal if file does not exist
-  buf = alloc(BufSize)
-  p = cast[PByteArray](buf)
+  var buf = alloc(BufSize)
+  var p = cast[PByteArray](buf)
   while true: 
-    readBytes = readBuffer(bin, buf, bufSize)
+    var readBytes = readBuffer(bin, buf, bufSize)
     for i in countup(0, readBytes - 1): result = updateCrc32(p[i], result)
     if readBytes != bufSize: break 
   dealloc(buf)

compiler/nimrod.nim

@@ -50,7 +50,7 @@ proc ProcessCmdLine(pass: TCmdLinePass, command, filename: var string) =
       rawMessage(errArgsNeedRunOption, [])
   
 proc HandleCmdLine() = 
-  var start = getTime()
+  var start = epochTime()
   if paramCount() == 0: 
     writeCommandLineUsage()
   else: 
@@ -73,7 +73,8 @@ proc HandleCmdLine() =
         if gCmd == cmdRun:
           tccgen.run()
       if gCmd notin {cmdInterpret, cmdRun}: 
-        rawMessage(hintSuccessX, [$gLinesCompiled, $(getTime() - start)])
+        rawMessage(hintSuccessX, [$gLinesCompiled, 
+                   formatFloat(epochTime() - start, ffDecimal, 3)])
       if optRun in gGlobalOptions: 
         when defined(unix): 
           var prog = "./" & quoteIfContainsWhite(changeFileExt(filename, ""))
@@ -81,6 +82,7 @@ proc HandleCmdLine() =
           var prog = quoteIfContainsWhite(changeFileExt(filename, ""))
         execExternalProgram(prog & ' ' & arguments)
 
+#GC_disableMarkAndSweep()
 cmdLineInfo = newLineInfo("command line", -1, -1)
 condsyms.InitDefines()
 HandleCmdLine()

compiler/treetab.nim

@@ -1,7 +1,7 @@
 #
 #
 #           The Nimrod Compiler
-#        (c) Copyright 2008 Andreas Rumpf
+#        (c) Copyright 2011 Andreas Rumpf
 #
 #    See the file "copying.txt", included in this
 #    distribution, for details about the copyright.
@@ -12,13 +12,7 @@
 import 
   nhashes, ast, astalgo, types
 
-proc NodeTableGet*(t: TNodeTable, key: PNode): int
-proc NodeTablePut*(t: var TNodeTable, key: PNode, val: int)
-proc NodeTableTestOrSet*(t: var TNodeTable, key: PNode, val: int): int
-# implementation
-
 proc hashTree(n: PNode): THash = 
-  result = 0
   if n == nil: return 
   result = ord(n.kind)
   case n.kind
@@ -41,7 +35,6 @@ proc hashTree(n: PNode): THash =
       result = concHash(result, hashTree(n.sons[i]))
   
 proc TreesEquivalent(a, b: PNode): bool = 
-  result = false
   if a == b: 
     result = true
   elif (a != nil) and (b != nil) and (a.kind == b.kind): 
@@ -60,36 +53,31 @@ proc TreesEquivalent(a, b: PNode): bool =
     if result: result = sameTypeOrNil(a.typ, b.typ)
   
 proc NodeTableRawGet(t: TNodeTable, k: THash, key: PNode): int = 
-  var h: THash
-  h = k and high(t.data)
+  var h: THash = k and high(t.data)
   while t.data[h].key != nil: 
     if (t.data[h].h == k) and TreesEquivalent(t.data[h].key, key): 
       return h
     h = nextTry(h, high(t.data))
-  result = - 1
+  result = -1
 
-proc NodeTableGet(t: TNodeTable, key: PNode): int = 
-  var index: int
-  index = NodeTableRawGet(t, hashTree(key), key)
+proc NodeTableGet*(t: TNodeTable, key: PNode): int = 
+  var index = NodeTableRawGet(t, hashTree(key), key)
   if index >= 0: result = t.data[index].val
   else: result = low(int)
   
-proc NodeTableRawInsert(data: var TNodePairSeq, k: THash, key: PNode, val: int) = 
-  var h: THash
-  h = k and high(data)
+proc NodeTableRawInsert(data: var TNodePairSeq, k: THash, key: PNode, 
+                        val: int) = 
+  var h: THash = k and high(data)
   while data[h].key != nil: h = nextTry(h, high(data))
   assert(data[h].key == nil)
   data[h].h = k
   data[h].key = key
   data[h].val = val
 
-proc NodeTablePut(t: var TNodeTable, key: PNode, val: int) = 
-  var 
-    index: int
-    n: TNodePairSeq
-    k: THash
-  k = hashTree(key)
-  index = NodeTableRawGet(t, k, key)
+proc NodeTablePut*(t: var TNodeTable, key: PNode, val: int) = 
+  var n: TNodePairSeq
+  var k: THash = hashTree(key)
+  var index = NodeTableRawGet(t, k, key)
   if index >= 0: 
     assert(t.data[index].key != nil)
     t.data[index].val = val
@@ -103,13 +91,10 @@ proc NodeTablePut(t: var TNodeTable, key: PNode, val: int) =
     NodeTableRawInsert(t.data, k, key, val)
     inc(t.counter)
 
-proc NodeTableTestOrSet(t: var TNodeTable, key: PNode, val: int): int = 
-  var 
-    index: int
-    n: TNodePairSeq
-    k: THash
-  k = hashTree(key)
-  index = NodeTableRawGet(t, k, key)
+proc NodeTableTestOrSet*(t: var TNodeTable, key: PNode, val: int): int = 
+  var n: TNodePairSeq
+  var k: THash = hashTree(key)
+  var index = NodeTableRawGet(t, k, key)
   if index >= 0: 
     assert(t.data[index].key != nil)
     result = t.data[index].val

koch.nim

@@ -157,10 +157,8 @@ proc cleanAux(dir: string) =
       of "nimcache": 
         echo "removing dir: ", path
         removeDir(path)
-      of "dist", ".git":
-        nil
-      else:
-        cleanAux(path)
+      of "dist", ".git": nil
+      else: cleanAux(path)
     else: nil
 
 proc removePattern(pattern: string) = 

lib/core/threads.nim

@@ -100,7 +100,7 @@ when defined(Windows):
       stdcall, dynlib: "kernel32", importc: "WaitForMultipleObjects".}
 
   proc WaitForSingleObject(hHandle: THANDLE, dwMilliseconds: int32): int32 {.
-      stdcall, dynlib: "kernel32", importc: "WaitForSingleObject".}
+    stdcall, dynlib: "kernel32", importc: "WaitForSingleObject".}
 
   proc TerminateThread(hThread: THandle, dwExitCode: int32): int32 {.
     stdcall, dynlib: "kernel32", importc: "TerminateThread".}

lib/pure/collections/hashtables.nim

@@ -216,9 +216,16 @@ proc `[]=`*[A, B](t: TOrderedHashTable[A, B], key: A, val: B) =
     inc(t.counter)
 
 proc del*[A, B](t: TOrderedHashTable[A, B], key: A) =
-  ## deletes `key` from hash table `t`.
+  ## deletes `key` from hash table `t`. Warning: It's inefficient for ordered
+  ## tables: O(n).
   var index = RawGet(t, key)
   if index >= 0:
+    var i = t.first
+    while i >= 0:
+      var nxt = t.data[i].next
+      if nxt == index: XXX
+      i = nxt
+    
     t.data[index].slot = seDeleted
     dec(t.counter)
 

lib/system/cgprocs.nim

@@ -23,28 +23,39 @@ proc nimLoadLibraryError(path: string) {.compilerproc, noinline.}
 
 proc setStackBottom(theStackBottom: pointer) {.compilerRtl, noinline.}
 
-
 # Support for thread local storage:
-when false:
-  when defined(windows):
-    proc TlsAlloc(): int32 {.importc: "TlsAlloc", stdcall, dynlib: "kernel32".}
-    proc TlsSetValue(dwTlsIndex: int32, lpTlsValue: pointer) {.
-      importc: "TlsSetValue", stdcall, dynlib: "kernel32".}
-    proc TlsGetValue(dwTlsIndex: int32): pointer {.
-      importc: "TlsGetValue", stdcall, dynlib: "kernel32".}
+when defined(windows):
+  type
+    TThreadVarSlot {.compilerproc.} = distinct int32
 
-  else:
-    type
-      Tpthread_key {.importc: "pthread_key_t", header: "<sys/types.h>".} = int
+  proc TlsAlloc(): TThreadVarSlot {.
+    importc: "TlsAlloc", stdcall, dynlib: "kernel32".}
+  proc TlsSetValue(dwTlsIndex: TThreadVarSlot, lpTlsValue: pointer) {.
+    importc: "TlsSetValue", stdcall, dynlib: "kernel32".}
+  proc TlsGetValue(dwTlsIndex: TThreadVarSlot): pointer {.
+    importc: "TlsGetValue", stdcall, dynlib: "kernel32".}
   
-    proc pthread_getspecific(a1: Tpthread_key): pointer {.
-      importc: "pthread_getspecific", header: "<pthread.h>".}
-    proc pthread_key_create(a1: ptr Tpthread_key, 
-                            a2: proc (x: pointer) {.noconv.}): int32 {.
-      importc: "pthread_key_create", header: "<pthread.h>".}
-    proc pthread_key_delete(a1: Tpthread_key): int32 {.
-      importc: "pthread_key_delete", header: "<pthread.h>".}
+  proc ThreadVarAlloc(): TThreadVarSlot {.compilerproc, inline.} =
+    result = TlsAlloc()
+  proc ThreadVarSetValue(s: TThreadVarSlot, value: pointer) {.compilerproc.} =
+    TlsSetValue(s, value)
+  proc ThreadVarGetValue(s: TThreadVarSlot): pointer {.compilerproc.} =
+    result = TlsGetValue(s)
   
-    proc pthread_setspecific(a1: Tpthread_key, a2: pointer): int32 {.
-      importc: "pthread_setspecific", header: "<pthread.h>".}
+else:
+  type
+    Tpthread_key {.importc: "pthread_key_t", 
+                   header: "<sys/types.h>".} = distinct int
+    TThreadVarSlot {.compilerproc.} = Tpthread_key
+
+  proc pthread_getspecific(a1: Tpthread_key): pointer {.
+    importc: "pthread_getspecific", header: "<pthread.h>".}
+  proc pthread_key_create(a1: ptr Tpthread_key, 
+                          destruct: proc (x: pointer) {.noconv.}): int32 {.
+    importc: "pthread_key_create", header: "<pthread.h>".}
+  proc pthread_key_delete(a1: Tpthread_key): int32 {.
+    importc: "pthread_key_delete", header: "<pthread.h>".}
+
+  proc pthread_setspecific(a1: Tpthread_key, a2: pointer): int32 {.
+    importc: "pthread_setspecific", header: "<pthread.h>".}
 

lib/system/dyncalls.nim

@@ -1,7 +1,7 @@
 #
 #
 #            Nimrod's Runtime Library
-#        (c) Copyright 2010 Andreas Rumpf
+#        (c) Copyright 2011 Andreas Rumpf
 #
 #    See the file "copying.txt", included in this
 #    distribution, for details about the copyright.
@@ -21,8 +21,6 @@ proc rawWrite(f: TFile, s: string) =
 
 proc nimLoadLibraryError(path: string) =
   # carefully written to avoid memory allocation:
-  #stdout.write("could not load: ")
-  #quit(path)
   stdout.rawWrite("could not load: ")
   stdout.rawWrite(path)
   stdout.rawWrite("\n")

lib/system/gc.nim

@@ -23,7 +23,7 @@
 const
   CycleIncrease = 2 # is a multiplicative increase
   InitialCycleThreshold = 4*1024*1024 # X MB because cycle checking is slow
-  ZctThreshold = 256  # we collect garbage if the ZCT's size
+  ZctThreshold = 500  # we collect garbage if the ZCT's size
                       # reaches this threshold
                       # this seems to be a good value
 
@@ -294,31 +294,32 @@ proc initGC() =
 proc forAllSlotsAux(dest: pointer, n: ptr TNimNode, op: TWalkOp) =
   var d = cast[TAddress](dest)
   case n.kind
-  of nkNone: assert(false)
   of nkSlot: forAllChildrenAux(cast[pointer](d +% n.offset), n.typ, op)
   of nkList:
     for i in 0..n.len-1: forAllSlotsAux(dest, n.sons[i], op)
   of nkCase:
     var m = selectBranch(dest, n)
     if m != nil: forAllSlotsAux(dest, m, op)
+  of nkNone: assert(false)
 
 proc forAllChildrenAux(dest: Pointer, mt: PNimType, op: TWalkOp) =
   var d = cast[TAddress](dest)
   if dest == nil: return # nothing to do
   if ntfNoRefs notin mt.flags:
     case mt.Kind
-    of tyArray, tyArrayConstr, tyOpenArray:
-      for i in 0..(mt.size div mt.base.size)-1:
-        forAllChildrenAux(cast[pointer](d +% i *% mt.base.size), mt.base, op)
     of tyRef, tyString, tySequence: # leaf:
       doOperation(cast[ppointer](d)[], op)
     of tyObject, tyTuple, tyPureObject:
       forAllSlotsAux(dest, mt.node, op)
+    of tyArray, tyArrayConstr, tyOpenArray:
+      for i in 0..(mt.size div mt.base.size)-1:
+        forAllChildrenAux(cast[pointer](d +% i *% mt.base.size), mt.base, op)
     else: nil
 
 proc forAllChildren(cell: PCell, op: TWalkOp) =
   assert(cell != nil)
   assert(cell.typ != nil)
+  assert cell.typ.kind in {tyRef, tySequence, tyString}
   case cell.typ.Kind
   of tyRef: # common case
     forAllChildrenAux(cellToUsr(cell), cell.typ.base, op)
@@ -329,14 +330,57 @@ proc forAllChildren(cell: PCell, op: TWalkOp) =
       for i in 0..s.len-1:
         forAllChildrenAux(cast[pointer](d +% i *% cell.typ.base.size +%
           GenericSeqSize), cell.typ.base, op)
-  of tyString: nil
-  else: assert(false)
+  else: nil
 
 proc checkCollection {.inline.} =
   # checks if a collection should be done
   if recGcLock == 0:
     collectCT(gch)
 
+proc addNewObjToZCT(res: PCell) {.inline.} =
+  # we check the last 8 entries (cache line) for a slot that could be reused.
+  # In 63% of all cases we succeed here! But we have to optimize the heck
+  # out of this small linear search so that ``newObj`` is not slowed down.
+  # 
+  # Slots to try          cache hit
+  # 1                     32%
+  # 4                     59%
+  # 8                     63%
+  # 16                    66%
+  # all slots             68%
+  var L = gch.zct.len
+  var d = gch.zct.d
+  when true:
+    # loop unrolled for performance:
+    template replaceZctEntry(i: expr) =
+      c = d[i]
+      if c.refcount >=% rcIncrement:
+        c.refcount = c.refcount and not colorMask
+        d[i] = res
+        return
+    if L > 8:
+      var c: PCell
+      replaceZctEntry(L-1)
+      replaceZctEntry(L-2)
+      replaceZctEntry(L-3)
+      replaceZctEntry(L-4)
+      replaceZctEntry(L-5)
+      replaceZctEntry(L-6)
+      replaceZctEntry(L-7)
+      replaceZctEntry(L-8)
+      add(gch.zct, res)
+    else:
+      d[L] = res
+      inc(gch.zct.len)
+  else:
+    for i in countdown(L-1, max(0, L-8)):
+      var c = d[i]
+      if c.refcount >=% rcIncrement:
+        c.refcount = c.refcount and not colorMask
+        d[i] = res
+        return
+    add(gch.zct, res)
+
 proc newObj(typ: PNimType, size: int): pointer {.compilerRtl.} =
   # generates a new object and sets its reference counter to 0
   aquire(gch)
@@ -354,18 +398,7 @@ proc newObj(typ: PNimType, size: int): pointer {.compilerRtl.} =
   res.refcount = rcZct # refcount is zero, but mark it to be in the ZCT  
   assert(isAllocatedPtr(allocator, res))
   # its refcount is zero, so add it to the ZCT:
-  block addToZCT: 
-    # we check the last 8 entries (cache line) for a slot
-    # that could be reused
-    var L = gch.zct.len
-    var d = gch.zct.d
-    for i in countdown(L-1, max(0, L-8)):
-      var c = d[i]
-      if c.refcount >=% rcIncrement:
-        c.refcount = c.refcount and not colorMask
-        d[i] = res
-        break addToZCT
-    add(gch.zct, res)
+  addNewObjToZCT(res)
   when logGC: writeCell("new cell", res)
   gcTrace(res, csAllocated)  
   release(gch)

lib/system/mmdisp.nim

@@ -1,7 +1,7 @@
 #
 #
 #            Nimrod's Runtime Library
-#        (c) Copyright 2010 Andreas Rumpf
+#        (c) Copyright 2011 Andreas Rumpf
 #
 #    See the file "copying.txt", included in this
 #    distribution, for details about the copyright.

todo.txt

@@ -1,11 +1,13 @@
+* thread support: threadvar on Windows seems broken; 
+  add --deadlock_prevention:on|off switch
 - implicit ref/ptr->var conversion
-- warning for implicit openArray -> varargs convention
-- implement explicit varargs
 
 
 High priority (version 0.9.0)
 =============================
 
+- warning for implicit openArray -> varargs convention
+- implement explicit varargs
 - tests: run modules that contain "#RUN_ME", compile the other
   modules; run the GC tests
 - fix implicit generic routines
@@ -32,11 +34,8 @@ To implement
 
 * hash tables and sets; count tables; ordered dicts
 * distinct types for array/seq indexes
-
 * implement closures for the C code generator
 * GC: marker procs for native Nimrod GC and Boehm GC
-* thread support: threadvar on Windows seems broken; 
-  add --deadlock_prevention:on|off switch
 * built-in serialization