The core and the headless tools no longer use mutexes, condition variables,
spinlocks, std::atomic, std::thread or volatile flags. Threads hand off through
libretro-common's retro_atomic and rthreads plus a few small pieces on top of
them in Common/Thread: Thread, MpscQueue, EventCounter, ParkingLot waits and
ReaderGate. Every wait blocks until it's woken; nothing polls on a timer.
State that only one thread touches just loses its lock. The PSP filesystem,
sceIo and the savedata dialog now belong to the emulation thread: async reads
and writes run when they're queued and complete later in emulated time, and
the IO and savedata threads are gone. The friend finder only talks to the
adhoc server and hands what it gets to the emulation thread. GPU init always
runs on the thread that starts the game.
The Vulkan render and compile queues, pipeline and render pass caches, delete
list and SPIR-V cache, the GL render queue, the software renderer's jit caches,
the file loader caches, the web debugger, UPnP, input, savestates, logging and
the GE debugger all hand off through queues and atomics. The IR jit's spinning
profiler thread goes.
A CPU thread with nothing to run now sleeps until work is queued instead of
spinning. Headless with --debugger waits for a client while stopped, and ends
the run once every client that connected has left. Web server shutdown keeps
servicing the CPU queue until the server has finished.
Socket waits now block in select() on the socket plus a wake or cancel
socket (Common/Net/Cancel), so a stop or cancel ends them at once.
- HTTP: cancel flags become net::CancelToken; Connect waits once on all
addresses, receives wait instead of spinning, no DNS retry sleep.
- Adhoc: the friend finder and adhoc server block on their sockets with
a wake socket and a deadline; matching runs on a CoreTiming tick
instead of two threads (savestate section bumped).
- sceNetInet select/poll check without blocking and park the HLE thread,
re-checked from a CoreTiming event until ready or the emulated
timeout.
- Vendor the aemu_postoffice client (was a submodule) with no sleeps:
waits on the socket, close via shutdown and an eventcount, cancelable
connects, and lock-free session slot claims.
- PortManager waits without a timeout; PSP_InitWait replaces the
headless boot poll.
- TimeUtil: sleep_us/sleep_ms only outside the core; sleep_precise,
sleep_random, yield and the Windows timer period are gone.
- Unit test for the socket waits.
Cancel() worked on the plain HTTP path - cancelled_ is threaded down as
progress->cancelled and checked while connecting and reading - but on the naett
path it only set a flag that nothing looked at. The transfer ran to completion
and cancelling just relabelled the result afterwards. Cancelling a store icon
that scrolled away, or a homebrew download the user gave up on, kept using the
bandwidth either way.
naett has one hook for this: a body writer that takes less than it was given
fails the request. So HTTPSRequest installs its own writer, which refuses
everything once cancelled. That works on all four backends and needs nothing
from naettClose, which is only really safe on Android.
The catch is lifetime. The writer runs on naett's transfer thread, and a request
that's still going when we're torn down would then be writing into a destroyed
HTTPSRequest - which is why the buffer it writes into is a separate refcounted
sink rather than a member. Join() on an unfinished request parks the sink where
it won't be freed and lets the request go, so a chunk that lands afterwards
writes somewhere that still exists.
That path is shutdown-only: RequestManager only cancels from its destructor, and
Update() waits for Done() before joining. Join now also notices a request that
finished while nobody was polling, and closes it properly instead of abandoning
it. What's left leaking at that point is a request still in flight as the
process exits, which is what already happened, just deliberate now and logged as
such rather than as an error.
sleep_ms() should generally be avoided when possible. This can be used to try
to track down unnecessary sleeps by adding some logging.
This commit on its own doesn't actually add any logging.
libretroadmin