#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]
#rb none
#jira UE-72524
#ROBOMERGE-SOURCE: CL 5988868 in //UE4/Release-4.22/...
#ROBOMERGE-BOT: RELEASE (Release-4.22 -> Main)
[CL 5988908 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
#ROBOMERGE-SOURCE: CL 5437980 in //UE4/Release-4.22/...
#ROBOMERGE-BOT: RELEASE (Release-4.22 -> Main)
[CL 5437990 by ben marsh in Main branch]
* Removed code to invalidate makefiles when adding new source files. UBT should be reliable enough to make this determination itself nowadays, and ignored -invalidatemakefilesonly argument was causing modules to be recompiled.
* Fixed incorrect config section name when determining whether to allow hot reload from IDE. Now prevents hot reload from IDE when live coding is enabled.
* Added error message when trying to add a new class with Live Coding enabled.
* Added error messages when trying to start Live Coding after a hot reload has taken place.
* Added error messages when trying to hot reload with Live Coding enabled.
#jira UE-71253
#rb none
#ROBOMERGE-SOURCE: CL 5403464 in //UE4/Release-4.22/...
#ROBOMERGE-BOT: RELEASE (Release-4.22 -> Main)
[CL 5403485 by ben marsh in Main branch]
#rb none
#jira UE-71399
#ROBOMERGE-SOURCE: CL 5365389 in //UE4/Release-4.22/...
#ROBOMERGE-BOT: RELEASE (Release-4.22 -> Main)
[CL 5368509 by ben marsh in Main branch]
#rb none
#jira UE-71379
#ROBOMERGE-SOURCE: CL 5362145 in //UE4/Release-4.22/...
#ROBOMERGE-BOT: RELEASE (Release-4.22 -> Main)
[CL 5368489 by ben marsh in Main branch]
