LV2 Optimizations

[elad335]

• Reduce time spent while owning mutexes.
• Avoid situations in which the notified thread gets blocked again on the same mutex the notifier thread still holds.
• Add busy waiting before entering atomic wait.
• Make LV2 synchronization syscalls allocation-free using a node system. (nearly)
• Move memory unlocking outside of mutex ownership and make it conditional.
• Make sys_mutex lock-free, add some busy waiting in sys_mutex_lock.
• Make sys_lwmutex nearly lock-free.
• Do not lock IDM mutex if the preliminary ID check failed.
• Optimize shared_mutex for more than 2 concurrent threads.

In addition to improving performance for low theaded CPUs (8 threads or less), this pull request helps the performamce of more than 2 PPU threads (the most accurate value and the default yet may be slower than more threads).
This pr may improve loading times as well due to improved PPU performance.

Results of a test locking and unlocking 4 LV2 mutexes on 8 threads.
ppumain.self.zip

Master, 2 PPU threads: sample finished in 24.269772 seconds.
Master, 4 PPU threads: sample finished in 59.015042 seconds.
Pull request, 2 PPU threads: sample finished in 2.951544 seconds.
Pull request, 4 PPU threads: sample finished in 5.736856 seconds.

[elad335]

The latest commit reduces the time a made-up test finishes by 4 times compared to master, all the test does is lock and unlock sys_mutex_t on multiple threads. Keep in mind this won't scale as nicely to games.

[solarmystic]

Performance remains roughly the same, with similar CPU utilization in the games tested below:-

GOW 3
This PR - 99 FPS/72 1% FPS/60 0.1% FPS - 54% CPU Usage

Current master - 99 FPS/72 1% FPS/59 0.1% FPS - 54% CPU Usage

Persona 5
This PR - 80 FPS/66 FPS 1% FPS/58 0.1% FPS - 67% CPU Usage

Current master - 81 FPS/67 FPS 1% FPS/61 0.1% FPS - 67% CPU Usage

Demon's Souls
This PR - 81 FPS/58 1% FPS/52 0.1% FPS - 33% CPU usage

Current master - 81 FPS/58 1% FPS/51 0.1% FPS - 34% CPU usage

Tested on an i5-12400F/1070ti system

[elad335]

Same when increasing PPU threads count (debug tab)? Especially on low thread count cpus.

[elad335]

Added perf diff.

[Nekotekina]

What's PS3 performance of the test? Also is any game found that benefits from it?

[elad335]

Latest commit greatly narrows the gap between 4 PPU threads and 2. Keep in mind that this is a stress test, 4 PPU threads should still be faster in compatible games if you have enough threads. It also improves the preformance of other stuff using mutexes as well.

[Augusto7743]

Perhaps is possible see an better performance in low cpus (AMD FX).

[coolllman]

With this pr Infamous 2 not go ingame, freeze on loading
#12485

[NFSROADCHALLENGE]

gran turismo 6 bces01893 ver 1.5. no controller works, try xbox and ps4 controller no one works :(

[Augusto7743]

Have anyone tested in Intel TSX cpu with an OS disabled all security mitigations ? (spectre, meltdown and etc)