SPDX standardizes how source code conveys its copyright and licensing
information. See https://spdx.github.io/spdx-spec/1-rationale/ . SPDX
tags are adopted in many large projects, including things like the Linux
kernel.
When I added the software FMA path in 2c38d64 and made us use
it when determinism is enabled, I was assuming that either the
performance impact of software FMA wouldn't be too large or CPUs
that were too old to have FMA instructions were too slow to run
Dolphin well anyway. This was wrong. To give an example, the
netplay performance went from 60 FPS to 30 FPS in one case.
This change makes netplay clients negotiate whether FMA should
be used. If all clients use an x64 CPU that supports FMA, or
AArch64, then FMA is enabled, and otherwise FMA is disabled.
In other words, we sacrifice accuracy if needed to avoid massive
slowdown, but not otherwise. When not using netplay, whether to
enable FMA is simply based on whether the host CPU supports it.
The only remaining case where the software FMA path gets used
under normal circumstances is when an input recording is created
on a CPU with FMA support and then played back on a CPU without.
This is not an especially common scenario (though it can happen),
and TASers are generally less picky about performance and more
picky about accuracy than other users anyway.
With this change, FMA desyncs are avoided between AArch64 and
modern x64 CPUs (unlike before 2c38d64), but we do get FMA
desyncs between AArch64 and old x64 CPUs (like before 2c38d64).
This desync can be avoided by adding a non-FMA path to JitArm64 as
an option, which I will wait with for another pull request so that
we can get the performance regression fixed as quickly as possible.
https://bugs.dolphin-emu.org/issues/12542
With the SI poll line count fixed, pretty much all games are polling
twice per frame anyways, making this option superfluous. Since it's a
bit of a gross hack and makes DTMs incompatible with console, let's
just bin it.
Normally, SI is polled at a rate defined by the game, and we have to send the pad state to other clients on every poll or else we'll desync. This can result in fairly high bandwidth usage, especially with multiple controllers, mostly due to UDP/IP overhead.
This change introduces an option to reduce the SI poll rate to once per frame, which may introduce up to one frame of additional latency, but will reduce bandwidth usage substantially, which is useful for users on very slow internet connections.
Polling SI less frequently than the game asked for did not seem to cause any problems in my testing, so this should be perfectly safe to do.
Makes the enum values strongly-typed and prevents the identifiers from
polluting the PowerPC namespace. This also cleans up the parameters of
some functions where we were accepting an ambiguous int type and
expecting the correct values to be passed in.
Now those parameters accept a PowerPC::CPUCore type only, making it
immediately obvious which values should be passed in. It also turns out
we were storing these core types into other structures as plain ints,
which have also been corrected.
As this type is used directly with the configuration code, we need to
provide our own overloaded insertion (<<) and extraction (>>) operators
in order to make it compatible with it. These are fairly trivial to
implement, so there's no issue here.
A minor adjustment to TryParse() was required, as our generic function
was doing the following:
N tmp = 0;
which is problematic, as custom types may not be able to have that
assignment performed (e.g. strongly-typed enums), so we change this to:
N tmp;
which is sufficient, as the value is attempted to be initialized
immediately under that statement.
This excludes the second argument from template deduction.
Otherwise, it is required to manually cast the second argument to
the ConfigInfo type (because implicit conversions won't work).
e.g. to set the value for a ConfigInfo<std::string> from a string
literal, you'd need a ugly `std::string("yourstring")`.
7f0834c9 moved the locations of the Real XFB (now XFB to RAM) and
Disabled XFB (now Immediate Mode) settings. There are programs
other than Dolphin that parse DTM headers, so this is not good.
Note that Immediate XFB actually is the inversion of Disabled XFB.
I hope that's not too much of a problem...
* Add missing Language setting loading/saving. This was added after the
original OnionConfig PR, which is why support for it was missing.
* Change MovieConfigLoader to reuse ConfigInfos. Less duplication.
* Extract MovieConfigLoader::Save into SaveToDTM. The DTM should use
the current config and not just the movie layer. This makes more
sense than just saving the movie layer, which may not always exist,
and also fixes a crash that would happen when creating a new
recording because the movie layer wouldn't exist in that case.
(Plus, having to get the loader from the layer and call ChangeDTM
on it manually is not very pretty.)
Settings that come from the SYSCONF are now included in Dolphin's
config system as part of the base layer. They are handled in a
special way compared to other settings to make sure they are only
loaded from and saved to the SYSCONF (to avoid different, possibly
contradicting sources of truth).