mirror of https://github.com/bsnes-emu/bsnes.git
2 Commits
| Author | SHA1 | Message | Date |
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Tim Allen
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f5e5bf1772 |
Update to v100r16 release.
byuu says: (Windows users may need to include <sys/time.h> at the top of nall/chrono.hpp, not sure.) Unchangelog: - forgot to add the Scheduler clock=0 fix because I have the memory of a goldfish Changelog: - new icarus database with nine additional games - hiro(GTK,Qt) won't constantly write its settings.bml file to disk anymore - added latency simulator for fun (settings.bml => Input/Latency in milliseconds) So the last one ... I wanted to test out nall::chrono, and I was also thinking that by polling every emulated frame, it's pretty wasteful when you are using Fast Forward and hitting 200+fps. As I've said before, calls to ruby::input::poll are not cheap. So to get around this, I added a limiter so that if you called the hardware poll function within N milliseconds, it'll return without doing any actual work. And indeed, that increases my framerate of Zelda 3 uncapped from 133fps to 142fps. Yay. But it's not a "real" speedup, as it only helps you when you exceed 100% speed (theoretically, you'd need to crack 300% speed since the game itself will poll at 16ms at 100% speed, but yet it sped up Zelda 3, so who am I to complain?) I threw the latency value into the settings file. It should be 16, but I set it to 5 since that was the lowest before it started negatively impacting uncapped speeds. You're wasting your time and CPU cycles setting it lower than 5, but if people like placebo effects it might work. Maybe I should let it be a signed integer so people can set it to -16 and think it's actually faster :P (I'm only joking. I took out the 96000hz audio placebo effect as well. Not really into psychological tricks anymore.) But yeah seriously, I didn't do this to start this discussion again for the billionth time. Please don't go there. And please don't tell me this WIP has higher/lower latency than before. I don't want to hear it. The only reason I bring it up is for the fun part that is worth discussing: put up or shut up time on how sensitive you are to latency! You can set the value above 5 to see how games feel. I personally can't really tell a difference until about 50. And I can't be 100% confident it's worse until about 75. But ... when I set it to 150, games become "extra difficult" ... the higher it goes, the worse it gets :D For this WIP, I've left no upper limit cap. I'll probably set a cap of something like 500ms or 1000ms for the official release. Need to balance user error/trolling with enjoyability. I'll think about it. [...] Now, what I worry about is stupid people seeing it and thinking it's an "added latency" setting, as if anyone would intentionally make things worse by default. This is a limiter. So if 5ms have passed since the game last polled, and that will be the case 99.9% of the time in games, the next poll will happen just in time, immediately when the game polls the inputs. Thus, a value below 1/<framerate>ms is not only pointless, if you go too low it will ruin your fast forward max speeds. I did say I didn't want to resort to placebo tricks, but I also don't want to spark up public discussion on this again either. So it might be best to default Input/Latency to 0ms, and internally have a max(5, latency) wrapper around the value. |
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Tim Allen
|
ca277cd5e8 |
Update to v100r14 release.
byuu says:
(Windows: compile with -fpermissive to silence an annoying error. I'll
fix it in the next WIP.)
I completely replaced the time management system in higan and overhauled
the scheduler.
Before, processor threads would have "int64 clock"; and there would
be a 1:1 relationship between two threads. When thread A ran for X
cycles, it'd subtract X * B.Frequency from clock; and when thread B ran
for Y cycles, it'd add Y * A.Frequency from clock. This worked well
and allowed perfect precision; but it doesn't work when you have more
complicated relationships: eg the 68K can sync to the Z80 and PSG; the
Z80 to the 68K and PSG; so the PSG needs two counters.
The new system instead uses a "uint64 clock" variable that represents
time in attoseconds. Every time the scheduler exits, it subtracts
the smallest clock count from all threads, to prevent an overflow
scenario. The only real downside is that rounding errors mean that
roughly every 20 minutes, we have a rounding error of one clock cycle
(one 20,000,000th of a second.) However, this only applies to systems
with multiple oscillators, like the SNES. And when you're in that
situation ... there's no such thing as a perfect oscillator anyway. A
real SNES will be thousands of times less out of spec than 1hz per 20
minutes.
The advantages are pretty immense. First, we obviously can now support
more complex relationships between threads. Second, we can build a
much more abstracted scheduler. All of libco is now abstracted away
completely, which may permit a state-machine / coroutine version of
Thread in the future. We've basically gone from this:
auto SMP::step(uint clocks) -> void {
clock += clocks * (uint64)cpu.frequency;
dsp.clock -= clocks;
if(dsp.clock < 0 && !scheduler.synchronizing()) co_switch(dsp.thread);
if(clock >= 0 && !scheduler.synchronizing()) co_switch(cpu.thread);
}
To this:
auto SMP::step(uint clocks) -> void {
Thread::step(clocks);
synchronize(dsp);
synchronize(cpu);
}
As you can see, we don't have to do multiple clock adjustments anymore.
This is a huge win for the SNES CPU that had to update the SMP, DSP, all
peripherals and all coprocessors. Likewise, we don't have to synchronize
all coprocessors when one runs, now we can just synchronize the active
one to the CPU.
Third, when changing the frequencies of threads (think SGB speed setting
modes, GBC double-speed mode, etc), it no longer causes the "int64
clock" value to be erroneous.
Fourth, this results in a fairly decent speedup, mostly across the
board. Aside from the GBA being mostly a wash (for unknown reasons),
it's about an 8% - 12% speedup in every other emulation core.
Now, all of this said ... this was an unbelievably massive change, so
... you know what that means >_> If anyone can help test all types of
SNES coprocessors, and some other system games, it'd be appreciated.
----
Lastly, we have a bitchin' new about screen. It unfortunately adds
~200KiB onto the binary size, because the PNG->C++ header file
transformation doesn't compress very well, and I want to keep the
original resource files in with the higan archive. I might try some
things to work around this file size increase in the future, but for now
... yeah, slightly larger archive sizes, sorry.
The logo's a bit busted on Windows (the Label control's background
transparency and alignment settings aren't working), but works well on
GTK. I'll have to fix Windows before the next official release. For now,
look on my Twitter feed if you want to see what it's supposed to look
like.
----
EDIT: forgot about ICD2::Enter. It's doing some weird inverse
run-to-save thing that I need to implement support for somehow. So, save
states on the SGB core probably won't work with this WIP.
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