If we're shrinking the L1 cache then we just deleted the entry that we
just looked up. Add it back to ensure we don't get yet another lookup
for this entry.
Growing widens L1PointerMask without touching the table, so an entry whose
address has the new mask bit set sits where InvalidateCache no longer looks,
and a later shrink hands it back to the JIT. Wipe [0, old) on grow, the way
the shrink wipes [new, MAX); the still-valid entries go with it.
Compute a bucket hash and use it in the cache path to avoid grouping entries
that will never make sense together. Don't trust the path, though, and also
lace it into the keys themselves, so that eg. a RO cache miss can never turn
into corruption.
Keep a readable metadata entry at the beginning of the cache, with readable
version, bitness and serialized config.
Use printable characters in FOZ key names as intended.
We were assuming that SHLD undefined behaviour matches SHL, but the
specification actually changes a `ge` comparison to `gt`, which means a
shift of 16 isn't UB!
Thanks to the impeccable @OFFTKP in #5842 for bringing this up as it took a bit
for me to figure out what was actually wrong here. I modified their
unittest to cover more just to ensure we don't break it.
As long as the hash is smaller than 64-bits we can just return the bits
encoded directly. Codegen slightly changes with this packed
representation, but doesn't really matter.
Also removes ICacheLineSize as that doesn't actually affect codegen for
us. Once we add 27 more HostFeatures we can switch the hash over to
XXH3.
We actually never use this anymore, we instead always pass zero for
both, and then rely on the thread inheritance model or setting the
values manually. Now that we expose visibility of the
InternalThreadState to the frontend they just access it directly.
Just a smidge of cleanup, NFC.
FEX Relocations now live at an offset from the `CodeData.BlockBegin` of the
code. Regardless of where the relocation moves to, it should always be
relative to that address. This is what makes it PIC compatible.
We were preemptively offsetting the relocation location to be relative
to the memory base in the buffer, which is unnecessary and causes code
caching to basically relocate twice to get the real location.
So in JIT.cpp, stop relocating the offsets, they're already relative to
`BlockBegin`, which is offset 0.
Then when storing the relocation, stop relocating offsets AGAIN because it's
already relative to the code being serialized.
Then when loading the relocations in `CodeCache::ApplyCodeRelocations`
stop relocating offsets YET ANOTHER TIME.
All this is to say that relocation offsets are already PIC and relative
to offset 0, so we don't need to do it three times.
I accidentally replaced a couple usages of `AllocatedSize` with
`GetAllocatedSize()`. This resulted in a JIT buffer that ran out of
space would actually allocate a slightly smaller buffer each time, and
then it cascades downwards resulting in catastrophic performance.
Fix the use in `SharedCodeBufferManager.cpp` and `Core.cpp` which were
incorrect and renames the function to be more explicit.
Noticed while taking a look at the relocations that we were technically
not doing alignment before writing down code size.
- Make sure Align16B isn't used with unaligned code with assert
- Switch an `Align` over to `Align(16)` to force 16-byte alignment
- Without NOP insertion, as this is data at this point, so just zeros.
- Record data size after that alignment
- Remove the `Align16B` that occurred afterwards
- Previous query between alignments would leave us with up to 12 bytes
unaccounted for.
- Ensure everything is using the correct sizes by not querying again
- Ensure that emission buffer abuse can't happen by zeroing the buffer.
The various places that were using the CodeBuffer object were using
internal implementation details that are changing as we move over to a
bitmap allocator.
Preempt this by hiding some of the implementation details early without
changing behaviour. `GetBufferBase` is still technically leaking some of
the internal details, but it needs changes around how relocations are
being handled and how the disk cache validation works in order to handle
that right now.
Should be no functional change.
With all Stores happening on the same thread now, we can also make locking
more granular for extra perf. Move to positioned IO for everything, as we
can't reliably track the cursor with that faster locking model.
Add some bounds checking to index population to protect against corruption.
It's soon going to change how these buffers are managed, where the
CodeBuffer is going to manage its own allocations soon once it changes
over to the bitmap allocator. Additionally the Manager class is actually
going to do proper management, pooling, and invalidation handling.
Split the task preemptively before we switch to the bitmap allocator to
reduce churn. A little change in the CodeCache where it needs to query
the codebuffer directly rather than the context, but fairly safe.
Shouldn't be any real behaviour change.
Serializes code blocks to disk - only blocks coming from known regions, for now
Disabled by default, key and versioning still needs work, but works for testing
This removes the fairly long lived lock that the buffer allocator held
while doing significantly more work than intended while holding that
lock.
As the first step towards moving over to the atomic bitmap allocator,
change this to be atomic to closer match what the new allocator is
doing. Since we are just doing linear allocations, this is an easy
convert and should give a good stutter improvement.
The two page-size extensions are a nop so might as well as enable them.
For the debug flag, we already set the duplicated flag in 8000_0001.edx, but missed this one.
Doesn't add anything new for the FEX side, but Burnout Paradise (and
remastered) is incorrectly checking for SSE2 support by checking if this is set.
Closes#5805 although their (ML?) write-up was incorrect.
NFC
- Renames CodeBufferManager to SharedCodeBufferManager to be more
explicit about it being shared between threads
- Renames `CodeBuffers` to `SharedCodeBuffers` to make it more explicit
about sharing these buffers between threads.
- Separates the Manager to its own file so it is distinct from the rest
of the CPUBackend code
Makes it easier to parse ownership and lifetime semantics of these
buffers.
Now that we have VMA region naming enabled on JIT buffers, this is no
longer used. Confirming a region is a JIT buffer is now just a case of
comparing the name that shows up in `/procfs/maps` rather than dumping
the first bytes of an unknown region.
`TempAllocator` was a bit too opaque as to what the allocator was for,
so I kept needing to lookup its usage every couple of months. Rename it
to `TempCodeBufferAllocator` so I can remember that it is a temporary
allocator for the staging JIT code buffer more easily.
NFC
We don't conditionally add any passes, so we can simplify the interface
so that we just add all existing passes at once. Makes the core
initialization process a little more straightforward.
This both take a void*, so the casting is unnecessary to begin with,
since this would occur anyway without it. We can also avoid a
duplication to reduce line noise.
Ryan Houdek