the speed of deserializing code. The current startup
time improvement for V8 is around 6%, but code deserialization
is speeded up disproportionately, and we will soon have more
code in the snapshot.
* Removed support for deserializing into large object space.
The regular pages are 1Mbyte now and that is plenty. This
is a big simplification.
* Instead of reserving space for the snapshot we actually
allocate it now. This removes some special casing from
the memory management and simplifies deserialization since
we are just bumping a pointer rather than calling the
normal allocation routines during deserialization.
* Record in the snapshot how much we need to boot up and
allocate it instead of just assuming that allocations in
a new VM will always be linear.
* In the snapshot we always address an object as a negative
offset from the current allocation point. We used to
sometimes address from the start of the deserialized data,
but this is less useful now that we have good support for
roots and repetitions in the deserialization data.
* Code objects were previously deserialized (like other
objects) by alternating raw data (deserialized with memcpy)
and pointers (to external references, other objects, etc.).
Now we deserialize code objects with a single memcpy,
followed by a series of skips and pointers that partially
overwrite the code we memcopied out of the snapshot.
The skips are sometimes merged into the following
instruction in the deserialization data to reduce dispatch
time.
* Integers in the snapshot were stored in a variable length
format that gives a compact representation for small positive
integers. This is still the case, but the new encoding can
be decoded without branches or conditional instructions,
which is faster on a modern CPU.
Review URL: https://chromiumcodereview.appspot.com/10918067
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12505 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
1. heap-inl.h has a function Heap::_inline_get_heap_ that calls
Isolate::Current() defined in isolate.h, so heap-inl.h requires
isolate.h.
2. Isolate has an embedded Heap member, so isolate.h requires heap.h.
3. heap.h has inline functions functions defined that call
Heap::_inline_get_heap_, so heap.h requires heap-inl.h (!).
The upshot is that all three need to be included wherever one is. A
simpler way is to break the cycle by moving the inlined functions in
heap.h to heap-inl.h.
R=vegorov@chromium.org
BUG=
TEST=
Review URL: https://chromiumcodereview.appspot.com/9121033
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10539 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Currently weak handles retain an object for another GC round (oftem times,
major GC round.) Instrumenting Chromium shows that navigation leaves
many global objects which are only collected in next go. Let's
attempt to collect more garbage when approacing OOM condition.
This is a better version of rolled out r5455: now it's correctly
rebuilds object groups between additional GCs.
Review URL: http://codereview.chromium.org/4295004
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5761 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Currently weak handles retain an object for another GC round (oftem times,
major GC round.) Instrumenting Chromium shows that navigation leaves
many global objects which are only collected in next go. Let's
attempt to collect more garbage when approacing OOM condition.
Review URL: http://codereview.chromium.org/3327021
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5455 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Changed the disposal of external string resources to call a virtual Dispose method on the resource. The default inplementation of Dispose deletes the object and will capture the delete operator matching the new operator used to allocate the object.
Review URL: http://codereview.chromium.org/2658008
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4816 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
- New сardmarking write barrier handles large objects and normal objects in a similar fashion (no more additional space for pointer tracking is required, no conditional branches in WB code).
- Changes to enable oldspaces iteration without maps decoding:
-- layout change for FixedArrays: length is stored as a smis (initial patch by
Kevin Millikin)
-- layout change for SharedFunctionInfo: integer fields are stored as smi on
arm, ia32 and rearranged on x64.
-- layout change for String: meaning of LSB bit is fliped (1 now means hash not
computed); on x64 padding is added.
-- layout of maps is _not_ changed. Map space is currently iterated in a special
way.
Review URL: http://codereview.chromium.org/2144006
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4715 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
-- layout change for FixedArrays: length is stored as a smis (initial patch by Kevin Millikin)
-- layout change for SharedFunctionInfo: integer fields are stored as smi on arm, ia32 and rearranged on x64.
-- layout change for String: meaning of LSB bit is fliped (1 now means hash not computed); on x64 padding is added.
-- layout of maps is _not_ changed. Map space is currently iterated in a special way.
- Cardmarking write barrier. New barrier handles large objects and normal objects in a similar fashion (no more additional space for pointer tracking is required, no conditional branches in WB code).
Review URL: http://codereview.chromium.org/2101002
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4685 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
registration of external references in Proxy objects).
I moved the declaration of the two functions to stub-cache.h
because with all the types they use it's hard to declare them
anywhere else. But the actual definition is still in runtime.cc
near to the place where they are used.
Review URL: http://codereview.chromium.org/1079012
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4231 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
true. The rules are:
1. Heap::AllocateRaw can normally handle allocation requests in new
space even when always_allocate() is true. It properly retries
failed allocation in the second 'retry' space.
2. Heap::Allocate can normally handle allocation requests in new
space.
3. We only need to check always_allocate() when explicitly requesting
allocation in new space via Heap::new_space().AllocateRaw().
4. The exception to these rules is fixed arrays with size such that
MaxObjectSizeInPagedSpace < size <= MaxObjectSizeInNewSpace (ie,
those that will be allocated in new space and promoted to large
object space). They cannot be allocated in new space via
Heap::Allocate or Heap::AllocateRaw, because the retry logic does
not know to allocate extra remembered set bits when retrying in
large object space.
Review URL: http://codereview.chromium.org/518007
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3535 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
On 32-bit the maps are now aligned on a 32-byte boundary in order to encode more maps during compacting GC. The actual size of a map on 32-bit is 28 bytes making this change waste 4 bytes per map.
On 64-bit the encoding for compacting GC is now using more than 32-bits and the maps here are still pointer size aligned. The actual size of a map on 64-bit is 48 bytes and this change does not intruduce any waste.
My choice of 16 bits for kMapPageIndexBits for 64-bit should give the same maximum number of pages (8K) for map space. As maps on 64-bit are larger than on 32-bit the total number of maps on 64-bit will be smaller than on 32-bit. We could consider raising this to 17 or 18.
I moved the kPageSizeBits to globals.h as the calculation of the encoding really depended on this.
There are still an #ifdef/#endif in objects.h and this constant could be moved to globaks.h as well, but I kept it together with the related constants.
All the tests run in debug mode with additional options --gc-global --always-compact as well (except for a few tests on which also fails before this change when run with --gc-global --always-compact).
BUG=http://code.google.com/p/v8/issues/detail?id=524
BUG=http://crbug.com/29428
TEST=test/mjsunit/regress/regress-524.js
Review URL: http://codereview.chromium.org/504026
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3481 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Instead of weak handles external strings use a separate table. This
table uses 5 times less memory than weak handles. Moreover, since we
don't have to follow the weak handle callback protocol we can collect
the strings faster and even on scavenge collections.
Review URL: http://codereview.chromium.org/467037
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3439 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
The different length string types was used to encode the string length and the hash in one field. This is now split into two fields one for length and one for hash. The hash field still encodes the array index of the string if it has one. If an array index is encoded in the hash field the string length is added to the top bits of the hash field to avoid a hash value of zero.
On 32-bit this causes an additional 4 bytes to be used for all string objects. On 64-bit this will be half on average dur to pointer alignment.
Review URL: http://codereview.chromium.org/436001
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3350 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
If V8 is holding on to a lot of external memory, we attempt to clean
it up even if we do not get an allocation failure. Since tiny V8
objects can hold on to a lot of external memory, we might run out of
external memory while waiting for a normal allocation failure.
Review URL: http://codereview.chromium.org/155916
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2519 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
space is similar to map space in that it has fixed-size objects. A
common superclass for a space with fixed size objects is used for the
map space and cell space.
Allocate all cells in cell space. Handle it during all GCs. Modify
the free-list node representation (so that the size is not at a fixed
offset in all cells) to allow two-pointer free-list nodes. Clean up
some stuff in the MC collector.
Review URL: http://codereview.chromium.org/155211
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2411 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This issue was raised by Brett Wilson while reviewing my changelist for readability. Craig Silverstein (one of C++ SG maintainers) confirmed that we should declare one namespace per line. Our way of namespaces closing seems not violating style guides (there is no clear agreement on it), so I left it intact.
Review URL: http://codereview.chromium.org/115756
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2038 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
in the old generation while its remembered set is being swept for
pointers into the young generation. This is done by delaying the
copying of promoted objects from when they are first encountered and
promoted to only when their body is visited.
Review URL: http://codereview.chromium.org/115086
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@1971 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
