V8 engine can be bound to particular thread for the needed processing thus there is
no need to change most of the code.

Static data can be collected like this:

#include "utils.h"
#include "platform.h"

namespace disasm {
  class DisassemblerData;
}

namespace v8 {
namespace internal {
class ThreadManager;
class V8;
class StackGuard;
class Top;
class GlobalHandles;
class Heap;
class ContextSlotCache;
class KeyedLookupCache;
class DescriptorLookupCache;
class TranscendentalCaches;
class CompilationCache;
class Counters;
class StubCache;
class MarkCompactCollector;
class HandleScopeImplementer;
class Logger;
class Bootstrapper;
class Builtins;
class RelocatableData;
class RegExpStack;
class Scanner;
class Compiler;
class StorageData;
class ZoneData;
class ApiData;
class CodeGeneratorData;
class ObjectsData;
class RuntimeData;
class StatsTableData;
class ExecutionData;
class AssemblerData;
class ExternalReferenceTable;
#ifdef ENABLE_DEBUGGER_SUPPORT
class Debug;
class DebuggerAgent;
#endif
}

class V8Context {
public:
  internal::ThreadManager& thread_manager_;
  internal::V8& v8_;
  internal::Top& top_;
  internal::GlobalHandles& global_handles_;
  internal::Heap& heap_;
  internal::StackGuard& stack_guard_;
  internal::ContextSlotCache& context_slot_cache_;
  internal::DescriptorLookupCache& descriptor_lookup_cache_;
  internal::KeyedLookupCache& keyed_lookup_cache_;
  internal::TranscendentalCaches& transcendental_caches_;
  internal::CompilationCache& compilation_cache_;
  internal::Counters& counters_;
  internal::MarkCompactCollector& mark_compact_collector_;
  internal::StubCache& stub_cache_;
  internal::HandleScopeImplementer& handle_scope_implementer_;
  internal::Logger& logger_;
  internal::Bootstrapper& bootstrapper_;
  internal::Builtins& builtins_;
  internal::RelocatableData& relocatable_data_;
  internal::RegExpStack& reg_exp_stack_;
  internal::Scanner& scanner_;
  internal::Compiler& compiler_;
  internal::StorageData& storage_data_;
  internal::ZoneData& zone_data_;

  internal::ApiData& api_data;
  internal::ObjectsData* objects_data;
  internal::CodeGeneratorData& code_generator_data_;
  internal::RuntimeData* runtime_data_;
  internal::ExecutionData* execution_data_;
  internal::StatsTableData& stats_table_data_;
  internal::ExternalReferenceTable* external_reference_table_;

  #ifdef ENABLE_DEBUGGER_SUPPORT
  internal::Debug& debug_;
  internal::DebuggerAgent* debugger_agent_;
  #endif

  //#ifdef ENABLE_DISASSEMBLER
  disasm::DisassemblerData* disassembler_data_;
  //#endif
  
  internal::AssemblerData* assembler_data_;

  V8Context();
  ~V8Context();
private:
  DISALLOW_COPY_AND_ASSIGN(V8Context);
};

#ifndef V8_SINGLE_THREADED
extern internal::Thread::LocalStorageKey default_context;

inline V8Context* v8_context() {
  return reinterpret_cast<V8Context*>(internal::Thread::GetThreadLocal(default_context));
}
#else
extern V8Context* default_context;

inline V8Context* v8_context() {
  return default_context;
}
#endif

}

---------------
prototype patch for i386 attached

Most of static invokations for top level internal classes like 
Heap::PerformScavenge() 
become 
v8_context()->heap_.PerformScavenge();
-------
prototype patch for i386 + updated tests attached

v8mt_with_tests.patch 1.1 MB   Download

Wow, this is the most ambitious patch I've ever seen!

I'm having some trouble getting it patched in though.  The patch says it's against 
3237 but I get conflicts when I try to patch it into that revision on bleeding_edge.  
Would you consider updating the patch to be against the latest bleeding_edge and 
uploading it to our code review server (see 
http://www.chromium.org/developers/contributing-code).

Also, do you have any performance measurements?  How does this affect the v8 
benchmarks for instance?

I attached archieved complete sources (v8mt.rar) of the prototype for anybody
interested to play with. One needs to define SEVERAL_V8_IN_PROCESS in include/v8.h,
please see sample win32 program V8M.cpp. 
The changes are quite massive and it takes some time for rebasing :) I will post
smaller patches for the easier review and incremental process.
As to performance, I've put all benchmark js files into one (benchmarks/test.js ) and
run it five times.
Original v8 RELEASE (scons mode=release library=static snapshot=on) version yields
following results:
All benchmark done for 54 seconds:
Richards: 1136
DeltaBlue: 1198
Crypto: 776
RayTrace: 1865
EarleyBoyer: 2319
RegExp: 389
Splay: 1514
Score: 1152

Richards: 1130
DeltaBlue: 1232
Crypto: 787
RayTrace: 1822
EarleyBoyer: 2413
RegExp: 384
Splay: 1498
Score: 1157

Richards: 1185
DeltaBlue: 1225
Crypto: 793
RayTrace: 1858
EarleyBoyer: 2411
RegExp: 380
Splay: 1445
Score: 1160

Richards: 1142
DeltaBlue: 1216
Crypto: 767
RayTrace: 1823
EarleyBoyer: 2296
RegExp: 372
Splay: 1450
Score: 1134

Richards: 1142
DeltaBlue: 1208
Crypto: 763
RayTrace: 1831
EarleyBoyer: 2392
RegExp: 380
Splay: 1525
Score: 1150
----
Attached RELEASE version without several v8 instances in process:
Benchmark done for 55 seconds
Richards: 1155
DeltaBlue: 1180
Crypto: 768
RayTrace: 1847
EarleyBoyer: 2276
RegExp: 229
Splay: 1467
Score: 1057

Richards: 1142
DeltaBlue: 1196
Crypto: 769
RayTrace: 1804
EarleyBoyer: 2289
RegExp: 229
Splay: 1501
Score: 1059

Richards: 1140
DeltaBlue: 1199
Crypto: 772
RayTrace: 1790
EarleyBoyer: 2294
RegExp: 233
Splay: 1421
Score: 1053

Richards: 1161
DeltaBlue: 1241
Crypto: 778
RayTrace: 1841
EarleyBoyer: 2364
RegExp: 232
Splay: 1501
Score: 1079

Richards: 1166
DeltaBlue: 1212
Crypto: 780
RayTrace: 1822
EarleyBoyer: 2299
RegExp: 232
Splay: 1501
Score: 1070

-------------- 
Attached RELEASE version with several v8 instances in process and one thread:
Benchmark done for 59 seconds
Richards: 1171
DeltaBlue: 1200
Crypto: 787
RayTrace: 1697
EarleyBoyer: 1975
RegExp: 214
Splay: 2064
Score: 1073

Richards: 1165
DeltaBlue: 1163
Crypto: 788
RayTrace: 1807
EarleyBoyer: 2048
RegExp: 215
Splay: 1120
Score: 993

Richards: 1171
DeltaBlue: 1216
Crypto: 788
RayTrace: 1804
EarleyBoyer: 2075
RegExp: 216
Splay: 1131
Score: 1004

Richards: 1161
DeltaBlue: 1187
Crypto: 791
RayTrace: 1811
EarleyBoyer: 2073
RegExp: 216
Splay: 1147
Score: 1002

Richards: 1162
DeltaBlue: 1199
Crypto: 785
RayTrace: 1813
EarleyBoyer: 2050
RegExp: 216
Splay: 1168
Score: 1003

Attached RELEASE version with several v8 instances in process and two threads (CPU
has two cores):
Benchmark done for 59 seconds
Richards: 1187
DeltaBlue: 1228
Crypto: 802
RayTrace: 1770
EarleyBoyer: 2030
RegExp: 220
Splay: 1134
Score: 1007

Richards: 1200
DeltaBlue: 1239
Crypto: 802
RayTrace: 1856
EarleyBoyer: 2064
RegExp: 220
Splay: 1095
Score: 1014

Richards: 1193
DeltaBlue: 1218
Crypto: 800
RayTrace: 1860
EarleyBoyer: 2005
RegExp: 220
Splay: 1145
Score: 1013

Richards: 1194
DeltaBlue: 1235
Crypto: 802
RayTrace: 1862
EarleyBoyer: 2003
RegExp: 217
Splay: 1159
Score: 1015

Richards: 1197
DeltaBlue: 1239
Crypto: 803
RayTrace: 1865
EarleyBoyer: 2022
RegExp: 221
Splay: 1160
Score: 1020

Richards: 1140
DeltaBlue: 1146
Crypto: 757
RayTrace: 1610
EarleyBoyer: 1907
RegExp: 207
Splay: 1980
Score: 1031

Richards: 1107
DeltaBlue: 1126
Crypto: 764
RayTrace: 1694
EarleyBoyer: 1973
RegExp: 208
Splay: 1044
Score: 948

Richards: 1106
DeltaBlue: 1150
Crypto: 754
RayTrace: 1720
EarleyBoyer: 1953
RegExp: 204
Splay: 1044
Score: 948

Richards: 1126
DeltaBlue: 1153
Crypto: 759
RayTrace: 1712
EarleyBoyer: 1985
RegExp: 206
Splay: 1046
Score: 955

Richards: 1130
DeltaBlue: 1159
Crypto: 762
RayTrace: 1751
EarleyBoyer: 1985
RegExp: 204
Splay: 1058
Score: 960

V8M.cpp 2.2 KB   Download

archieved sources file now contain cctest files

v8mt.rar 2.4 MB   Download

gcl is unable to upload patch with "Connection refused"
----- gcl changelist description
First patch for allowing several V8 instances in process:
- Introduced V8ContextProvider and V8ContextBinder classes to public api (include\v8.h),
first class is defined only if SEVERAL_V8_IN_PROCESS macro is defined
- Created v8::internal::V8Context class to hold the data of separate objects of v8
instance

- Created v8_context() inline function to return V8Context for accessing the data, 
in case SEVERAL_V8_IN_PROCESS not defined the function just returns global pointer
otherwise
the data is retrieved from thread local variable
- Moved static data of v8::internal::V8, static flag from v8::Locker, static callback
pointer 
 exception_behavior from api.cc into v8::internal::V8Data as instance variables

- Moved static data of v8::internal::ThreadManager, v8::internal::ContextSwitcher,
v8::internal::ThreadState,
static Thread::LocalStorageKey variables into v8::internal::ThreadManagerData
- Wrapped dtoa calls in conversions.cc with locking when SEVERAL_V8_IN_PROCESS

- Moved static data of v8::internal::Heap into v8::internal::HeapData as instance
variables.
- MarkObjectVisitor and UnmarkObjectVisitor allocated on stack instead of static
variables.
- static void MarkObjectRecursively(Object** p); becomes member of
v8::internal::MarkObjectVisitor
- static void UnmarkObjectRecursively(Object** p); becomes member of
v8::internal::UnmarkObjectVisitor
- Moved static data of heap.cc into v8::internal::PrivateHeapData as instance variables.
- static void MarkRootObjectRecursively(Object** root); moved to
v8::internal::PrivateHeapData

- static data and types of v8::internal::TranscendentalCache moved to
v8::internal::TranscendentalCacheData as 
instance variables / types.
- static data and types of v8::internal::DescriptorLookupCache moved to
v8::internal::DescriptorLookupCacheData 
as instance variables / types.
- static data and types of v8::internal::KeyedLookupCacheData moved to
v8::internal::KeyedLookupCacheDataData as 
instance variables / types

- static data of v8::internal::Zone, v8::internal::ZoneScope, v8::internal::Zone, 
  v8::internal::AssertNoZoneAllocation, v8::internal::Segment moved to
v8:internal::ZoneData

BUG=510
TEST=When SEVERAL_V8_IN_PROCESS is not defined (default) all tests should pass

Uploaded several_v8_in_process_1.patch for code review
http://codereview.chromium.org/435003

Current sources snapshot of http://codereview.chromium.org/435003

v8embeddable.rar 3.3 MB   Download

Sources available in V8 sources fork at git://github.com/nicity/Embeddable-V8.git