#jira
#rb none
#ROBOMERGE-OWNER: ben.marsh
#ROBOMERGE-AUTHOR: ben.marsh
#ROBOMERGE-SOURCE: CL 5993252 via CL 5993257 via CL 5995286
[CL 5995562 by ben marsh in Main branch]
Encoding improvements
* New hash table implementation
--- Move away from 16-bit hashes since we need more than 64k buckets to hold 2M entries efficiently
--- Change to CityHash64, which is faster and stronger
--- Remove hardcoded max limit
* NAME_INDEX changed from contigouos int to monotonically increasing int
--- Opens up for future deduplication schemes that are better than number suffix dedup.
--- Saves some memory since we don't need to maintain a contiguous array
--- Typed up to cause compile errors when used as integer directly
* Avoid touching data repeatedly, normal path only does single hash of data
* New constructor that allows supplying string length up front
* Avoid dynamic allocations in string conversions >= 128 characters
* Avoid extra copying when splitting numbers
* More efficient IsPureAnsi check
* Only do one global lazy initialization call instead of multiple
* Switch to faster RW locks
* Switch from single lock to sharded hash map with separate locks
* Memory optimizations that reduces per entry overhead: 4 bytes slots, 2 byte headers and don't store null terminator
Improved API & documentation
* Document that IsValid() rarely makes sense
* Hide global state such as GetNames()
* Reduce amount of implementation details visible in header
* NameTypes.h size down by ~1/3 while adding documentation, stronger type safety and new APIs
Future possibilities
* Memory savings: Removing public NAME_INDEX and global FName array allows using the 32-bit FNameEntryId for arbitrary deduplication schemes. This can save both actual stored strings memory by deduplication and half the size of FName instances from 8B to 4B in shipping / test configs by removing the number part.
* Implementation can be tweaked further, for instance could persist 32-bit slot index hash inside slot to increase encoding performance in development / debug at the cost of memory.
Perf & mem results for internal project:
* Editor startup wall time: 12% speedup, 22.0s -> 19.5s
--- Warm disk and asset registry cache
--- Some gains from nametable serialization improvements
--- Some of these gains might be from orthogonal asset discovery optimizations
* Win64 Test Client memory usage with ~400k names: 30.3Mb -> 22.2Mb
#rb steve.robb, pj.kack
#jira UE-59973
[CL 5774657 by Johan Torp in Dev-Core branch]
#rb none
#jira UE-71077
#ROBOMERGE-SOURCE: CL 5343160 in //UE4/Release-4.22/...
#ROBOMERGE-BOT: RELEASE (Release-4.22 -> Main)
[CL 5343162 by ben marsh in Main branch]
#rb none
#rnx
#jira
#ROBOMERGE-SOURCE: CL 5312261 in //UE4/Release-4.22/...
#ROBOMERGE-BOT: RELEASE (Release-4.22 -> Main)
[CL 5316163 by ben marsh in Main branch]
#rb none
#jira
#ROBOMERGE-SOURCE: CL 5307320 in //UE4/Release-4.22/...
#ROBOMERGE-BOT: RELEASE (Release-4.22 -> Main)
[CL 5314647 by ben marsh in Main branch]
Allows fast iteration of C++ changes without restarting the application. To use, select the "Live Coding (Experimental)" mode from the drop down menu next to the editor's compile button, or type "LiveCoding" into the console for a monolithic build. Press Ctrl+Alt+F11 to find changes and compile.
Changes vs standalone Live++ version:
* UBT is used to execute builds. This allows standard UE4 adaptive unity mode, allows us to reuse object files when we do regular builds, supports using any build executor allowed by UBT (XGE, SNDBS, etc..).
* Adding new source files is supported.
* Custom visualizer for FNames is supported via a weakly linked symbol in a static library (Engine/Extras/NatvisHelpers).
* Settings are exposed in the editor's project settings dialog.
* Standalone application has been rewritten as a Slate app ("LiveCodingConsole"). There is an additional option to start the program as hidden, where it will not be visible until Ctrl+Alt+F11 is hit. Similarly, closing the window will hide it instead of closing the application.
* Does not require a standalone licensed version of Live++.
Known issues:
* Does not currently support class layout changes / object reinstancing
#rb none
[FYI] Marc.Audy, Stefan.Boberg, Nick.Penwarden
#jira
#ROBOMERGE-SOURCE: CL 5304722 in //UE4/Release-4.22/...
#ROBOMERGE-BOT: RELEASE (Release-4.22 -> Main)
[CL 5309051 by ben marsh in Main branch]
