It's a software memory barrier, and not a very strong one. If the values it is
protecting are Atomic, that provides a stronger hardware memory barrier.
This patch removes it, and changes one of the values it was protecting from
|volatile| to Atomic. (The other value it was protecting was already Atomic.)
The eslint-plugin-mozilla currently searches for Mozilla Central root by
walking up from its installed dir. However, if the plugin is installed outside
of central, such as globally, it will not find the root. This changeset
retains that behaviour, but will also perform the same check from the current
working directly before failing.
MozReview-Commit-ID: 2L3JqLTuVDS
--HG--
extra : rebase_source : e24ddc726cb2470f7165f028f71416e942c44f87
This patch performs a refactoring to the internals of the profiler in order to
expose a function, profiler_suspend_and_sample_thread, which can be called from a
background thread to suspend, sample the native stack, and then resume the
target passed-in thread.
The interface was designed to expose as few internals of the profiler as
possible, exposing only a single callback which accepts the list of program
counters and stack pointers collected during the backtrace.
A method `profiler_current_thread_id` was also added to get the thread_id of the
current thread, which can then be passed by another thread into
profiler_suspend_sample_thread to sample the stack of that thread.
This is implemented in two parts:
1) Splitting SamplerThread into two classes: Sampler, and SamplerThread.
Sampler was created to extract the core logic from SamplerThread which manages
unix signals on android and linux, as well as suspends the target thread on all
platforms. SamplerThread was then modified to subclass this type, adding the
extra methods and fields required for the creation and management of the actual
Sampler Thread.
Some work was done to ensure that the methods on Sampler would not require
ActivePS to be present, as we intend to sample threads when the profiler is not
active for the Background Hang Reporter.
2) Moving the Tick() logic into the TickController interface.
A TickController interface was added to platform which has 2 methods: Tick and
Backtrace. The Tick method replaces the previous Tick() static method, allowing
it to be overridden by a different consumer of SuspendAndSampleAndResumeThread,
while the Backtrace() method replaces the previous MergeStacksIntoProfile
method, allowing it to be overridden by different consumers of
DoNativeBacktrace.
This interface object is then used to wrap implementation specific data, such as
the ProfilerBuffer, and is threaded through the SuspendAndSampleAndResumeThread
and DoNativeBacktrace methods.
This change added 2 virtual calls to the SamplerThread's critical section, which
I believe should be a small enough overhead that it will not affect profiling
performance. These virtual calls could be avoided using templating, but I
decided that doing so would be unnecessary.
MozReview-Commit-ID: AT48xb2asgV
Given that this basically hogs a core per Firefox process, this code only kicks in if you explicitly select a sub-millisecond resolution.
--HG--
extra : rebase_source : 58ca6f8f6537bc4b809e1634ed177c5d47fd499c
Bug 1359000 moved these functions from GeckoProfiler.h to platform.cpp, which
allowed a lot of follow-up simplifications. But it hurt performance.
This patch moves them back to GeckoProfiler.h and makes them |inline| again.
This required adding a second TLS pointer, sPseudoStack. Comments in the patch
explain why.
--HG--
extra : rebase_source : 4198e32b9e251f4014bce890936f4f85dabeb8ab
This removes the need for PROFILER_LIKELY_MEMORY_CONSTRAINED.
The patch also removes PROFILE_JAVA, USE_FAULTY_LIB, CONFIG_CASE_1,
CONFIG_CASE_2 and replaces all their uses with GP_OS_linux or GP_OS_android.
Finally, the patch removes a bogus |defined(GP_OS_darwin)| condition in
platform-linux-lul.cpp.
--HG--
extra : rebase_source : 77d1c625d65ddf551ab8cd4b962ae48c1a54466c
Mark Banner
Ryan VanderMeulen
Nicholas Nethercote
Iris Hsiao
Wes Kocher
Bryce Van Dyk
Michael Layzell
rforbes
Swapnesh Kumar Sahoo
Carsten "Tomcat" Book
David Major
Mike Hommey
Rajesh Kathiriya
Kris Maglione
Jan Beich
Florian Quèze
Ehsan Akhgari
Sebastian Hengst
Markus Stange
Mark Hammond
Steve Fink