Instead of relying on itimer signals from kernel, send them
ourselves from a separate thread. This disables an ability
to profile multiple VM threads on Linux, but it anyway doesn't
work on other platforms, so we need a common solution for
it (issue 913 created to track this).
Review URL: http://codereview.chromium.org/4000007
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5711 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Since 2.6.31 perf_events interface has been available in the
kernel. There's a nice tool called "perf" (linux-2.6/tools/perf) that
uses this interface and provides capabilities similar to oprofile. The
simplest form of its usage is just dumping the raw log (trace) of
events generated by the kernel. In this patch I'm adding a script
(tools/ll_prof.py) to build profiles based on perf trace and our code
log. All the heavy-lifting is done by perf. Compared to oprofile agent
this approach does not require recompilation and supports code moving
garbage collections.
Expected usage is documented in the ll_prof's help. Basically one
should run V8 under perf passing --ll-prof flag and then the produced
logs can be analyzed by tools/ll_prof.py.
The new --ll-prof flag enables logging of generated code object
locations and names (like --log-code), and also of their bodies, which
can be later disassembled and annotated by the script.
Review URL: http://codereview.chromium.org/3831002
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5663 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This patch manually randomizes the allocation address for PAGE_EXECUTE_READWRITE regions between kAllocationRandomAddressMin and kAllocationRandomAddressMax.
BUG=none
TEST=allocate lots of javascript code and check for contiguous allocations
Patch by Paul Mehta <pmehta@chromium.org>
Review URL: http://codereview.chromium.org/2832095
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5169 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This is to make possible enabling usage of the new profiling subsystem
in Chromium without much hassle. The idea is pretty simple: unless the
new profiling API is used, all works as usual, as soon as Chromium
starts to use the new API, it will work too.
Review URL: http://codereview.chromium.org/1635005
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4382 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
In browser (DevTools) mode, only non-native JS code and callbacks are reported.
Also, added "(garbage collector)" entry which accumulates samples count in GC state.
Trying to display "(compiler)" and "(external)" only brings confusion,
because it ends up in displaying scripts code under "(compiler)" node, and DOM
event handlers under "(external)" node, which looks weird.
Review URL: http://codereview.chromium.org/1523015
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4357 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
On 'usual' Linux systems in '/proc/self/maps' we encounter two entries
per library: one has 'rw-p' attrs and the other has 'r-xp'. While on
Android, I see 'rwxp' and 'r-xp' (both entries are marked executable.)
So I've added an explicit check for non-writability to leave only a
single record in the log file.
Review URL: http://codereview.chromium.org/661467
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4018 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
The problem appeared due to a fact that stubs doesn't create a stack
frame, reusing the stack frame of the caller function. When building
stack traces, the current function is retrieved from PC, and its
callees are retrieved by traversing the stack backwards. Thus, for
stubs, the stub itself was discovered via PC, and then stub's caller's
caller was retrieved from stack.
To fix this problem, a pointer to JSFunction object is now captured
from the topmost stack frame, and is saved into stack trace log
record. Then a simple heuristics is applied whether a referred
function should be added to decoded stack, or not, to avoid reporting
the same function twice (from PC and from the pointer.)
BUG=553
TEST=added to mjsunit/tools/tickprocessor
Review URL: http://codereview.chromium.org/546089
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3673 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
available. We use this to ensure that snapshots on MacOSX can
use SSE2 instructions. Also clean up and assertify the
handling of things we can't do when we are generating a
snapshot. Fix a bug in the new serialization tests where
they activated Snapshot::enable() too late after code had been
generated that assumed no snapshots.
Review URL: http://codereview.chromium.org/391051
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3301 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
- Restructured the entire function because:
During the simple style fix I discovered that this whole routine was
hard to read due to a general lack of comments. While adding comments I
realized that the function was also skipping entries if there were two
consecutive entries in the maps file.
Review URL: http://codereview.chromium.org/159659
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2603 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Previous implementation of sampler for OS X was copied from the Linux one. But BSD (OS X) and Linux has a very important difference in signal handling. LinuxThreads doesn't support the notion of process-directed signals. So, the SIGPROF signal was directed to the thread that installed the handler---the V8 thread. But on BSD, signal handling is implemented according to POSIX spec, where process-directed signal is to be handled by an arbitrary selected thread. By a coincidence, in V8's sample shell and in Chromium's test shell, V8's thread was picked almost every time, so sampling seemed working. But not in case of Chromium.
So, I've changed the implementation of profiler sampler to use the same scheme as on Windows---a dedicated thread with high priority is used to periodically pause and sample V8's thread.
Review URL: http://codereview.chromium.org/147150
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2315 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Change stack alignment on linux to 16 bytes to keep gcc 4.4 happy.
This fixes the mksnapshot segfault without requiring -fno-tree-vectorize
which just avoided the problem by not generating code with movdqa.
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2107 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
