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.
The libretro core is the frontend, and the headless tools are the test and
debugging hosts. The Windows, UWP, Android, iOS, macOS and SDL apps, the UI
framework and imgui go, along with what only they used: the Win32 debugger
hooks (g_frameMutex, the shutdown lock), JNI thread attachment, the Android
text drawer, RAIntegration, Discord, recent files, game installs, tilt input,
the audio resamplers, the control mapper, memstick moving and the remote ISO
and upload server modes. The web server keeps the debugger. The MSVC, Gradle
and ndk-build projects go too.
blocksActuallyRead rounded bytesRead up to the next whole block
unconditionally, intending to handle the legitimate case where the
very last block of the file is naturally shorter than BLOCK_SIZE
(cache_ is deliberately over-allocated for that). But it applied the
same rounding to any short read, including a genuine failure or a
dropped connection mid-file (this loader can sit on top of the whole
Remote ISO chain via CachingFileLoader/HTTPFileLoader when "Cache full
ISO in RAM" is enabled) - marking a block as fully cached when only a
few of its bytes were actually written. Since cache_ is malloc'd (not
zeroed), every later read of that block would serve uninitialized heap
memory as if it were real file data.
Only round up when the short read's end position exactly matches the
true end of the file.
Turns out these were needed after all. For some reason, on Windows and
Mac, <algorithm> gets auto-included by something else so I don't notice
when it's missing, and MSVC's include dependency tracker doesn't see it
either.
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.
Since the majority of the code is using ReadAt API already, map this to
a `readp` "syscall" which does not mutate any state about the file
descriptor therefore making it fairly safe multi-threading wise.
This allows to get rid of read-time mutexes in RamCachedFileLoader and
therefore fixes#9803
This way we don't get slow startup. This will also cache the CSO data,
for example, rather than the raw data, using up less RAM. It might even
be reasonable to enable on 32-bit.
libretroadmin