Fixes a header usage problem for MSVC, which complains about StaticString not having a constexpr constructor thus making the "make" method not constexpr.
- only signal waitAndRelease() when the corresponding job finishes and
only if there is waitAndRelease() active -- instead of signaling
every time a job ends.
- don't surrender time slice when attempting to steal a job and it fails
as long as some queue has jobs.
- check that we have to wait, because taking the lock
- add a benchmark
This change more than doubles the amount of jobs we can handle per
second (~965,000 jobs/s on Pixel3)
JobSystem::waitAndRelease used to spin to wait for the job to finish,
usually this wasn't a problem because the spinning thread was
able to handle other jobs. However, in cases where no job was
available it would actually spin in burn cpu cycles.
we now use a (separate) condition variable to handle that case.
In a lot of case the StaticString hash can be computed a compile time,
so we now take advantage of that.
Removed StaticString(const char*) ctor, and replaced it with a
StaticString::make() method.
Fixed a couple wrong uses of the old StaticString(const char*) ctor.
We simply don't emit unwind tables, which are not needed anyways since
we're compiling without exceptions. the combined saving for all four
targets we support is about 120K.
This seems to improve .aar's compression, for a total gain of 152 KiB.
We also disable stack-protector in the jni code, since it wasn't
enabled in libfilament.a anyways. However, we now compile all debug
builds with -fstack-protector
- make Profiler::readCounters() not inline as it didn't need to be,
it's not performance critical and it's sufficiently large.
- don't inline hasExtensions(), same reason.
We used to only wake up a job-queue if there was already some jobs
running, the idea was that the current thread would handle the new job
as soon as calling wait(). However, there is no guarantee that wait()
will be called anytime soon.
cv.signal() is not very expensive on Android/Linux, as we're using
a custom implementation.
An assert checking invariants would sometime trigger, the problem
was a logic error that would be exposed by a race when running out
of space in the list.
The root of the problem is that in one place we were not remapping the
-1 offset to nullptr, storing a pointer violating our invariants.
Also added more asserts!!!
We're using timed condition variable in one place, but the STL version
pulls in a lot of code because it does clock calculations in
"long double" (!!!!). Since we already had an implementation
of condition_variable, we just add the timed version.
This saves several KiB of code.
Also don't use unique_lock() lock/unlock because it can throw exceptions.
This removes a lot of heap allocations/deallocations, and reduces
code size. Most improvements come from using CString and
StaticString instead of std::string and better using move
semantics.
* Clean-up EntityManager a bit
- use tsl::robin_set instead of std::set (which should have been unordered::set
anyways).
- getListeners() now returns a vector which avoids to traverse a set twice.
Turns out that copying the set wasn't as efficient as I thought.
* Improve jobsystem a bit
We recently added a job reference counting mechanism, but we were a bit
too aggressive about taking/release references.
Also make the API more complete by adding explicit retain/release,
which is needed to allow several threads to wait on the same job.
Also improve futex code by inlining it.
* Minor clean-ups
- fix a couple usage of std::function
- fix a couple usage of std::string
- remove ALIGN_LOOP, which didn't work
- fix a couple explicit/noexcept
- virtual -> override
* Fix spelling typos and other minor clang-tidy
We used to assume 32-bytes cache lines when running on ARM 32-bit mode,
however, that was wrong because 32-bit mode doesn't change the cpu's
cache line. On all modern platforms we support, the cache line
is 64 bytes.
Set Job storage to 48 bytes on all platforms.
* Fix a reuse after free in the job system
Jobs were destroyed and recycled while still in use
by wait() or run(). To fix this we introduce reference-counting of
jobs.
Jobs start with a ref-count of 1, which is decremented when a job
naturally finishes. Additionally, all user-facing methods acquire
a reference for the duration of the call.
* Fix an API inconsistency with JobSystem
JobSystem's API lets the user create jobs but not destroy them.
Jobs are destroyed automatically, without a way for the caller to
know when that happens.
We now explicitly enforce that jobs are no longer valid when
wait() returns. Multiple concurrent wait() are allowed however.
This is enforced by clearing the job pointer upon returning
from JobSystem::wait(Job* job).
* Rename linked-list put/get to push/pop
* Better fix for Job use after free
There was still a race condition where a run()'ed
job could be destroyed before wait() was called,
wait would then use a destroyed object.
The available APIs now are:
run() - runs and destroys a job
runAndWait() - run, then waits for and destroys a job
runAndRetain() - runs and keep a reference to the job
wait() - waits and destroys a job
wait() can only be used with a job obtained with runAndRetain().
* Get rid of unused code
This version of parallel_for has use-after-free issues anyways,
since we changed the semantics of run/wait/etc...
* Fix decRef() memory order
decRef() must ensure that all access to the
object have happened before destroying it.
* Fix memory order in atomic linked list's pop()
It needs acquire semantic, since we want to make
sure that no read/write are reordered before the
pop() -- which returns an object to the caller.
* Fix memory order on runningJobCount
we needed acquire semantic when about to destroy
the last job -- it's similar to decRef.
* Comment usages of std::memory_order_*
* Fix AtomicFreeList A-B-A bug
Turns out AtomicFreeList was not immune to the ABA bug. W're fixing
it here by using a 64-bits CAS, which is available on aarch64 and armv7.
This does not add any build stuff or new sample code yet, it just does
some prep to our C++ codebase:
- Similar to Android, WebAssembly will not be using BlueGL. We were
using a mixture of #if and #ifdef when checking for the existence of
certain GL prototypes, but the latter is what we want in order to
build robustly with any GL headers. (We still perform run-time checks
for extensions, this doesn't change that.)
- Add a trivial ContextManager, does a bit more than Dummy since it
needs to create an actual driver. This doesn't get compiled yet, it
just adds files to the tree.
- WebAssembly does not support mmap, execinfo, or asm volatile.
