[sunzenshen]

Description

CHL2MPPlayerAnimState::ComputePoseParam_MoveYaw builds ConVarRef mp_slammoveyaw("mp_slammoveyaw") on every call. Each construction looks the cvar up by name with CCvar::FindVar, a linear, case-insensitive walk over every registered cvar. The function runs for every player on every usercmd on the server, and every frame for every player on the client, so this one lookup was the largest single cost in a bot match's server frame.

mp_slammoveyaw is defined in shared/Multiplayer/multiplayer_animstate.cpp, which both the client and the server build, and that file already reads it directly. This PR declares it extern and drops the ConVarRef; the mp_slammoveyaw.GetBool() line is unchanged. The value read is the live cvar value, as before: nothing is cached, so changing the cvar still takes effect at once.

Masterkatze identified this lookup cost earlier (unmerged "Cache mp_slammoveyaw" on their fps branch); this version reads the live cvar value instead of caching it once.

How to test

1. Play any map with bots (or players) and check that legs blend as before while moving in every direction.
2. mp_slammoveyaw 1 (development-only cvar) still snaps the move yaw while moving; mp_slammoveyaw 0 turns it off again.

Risk

None expected: same ConVar object, same value, no behavior change. ConVar::GetBool reads the parent ConVar's value, and the parent is the one FindVar returned.

Results

Linux dedicated server, Release builds of master (f426c22) with and without this commit, both with the test harness's match markers and a temporary timer around ComputePoseParam_MoveYaw (including its base class call) and around CServerGameDLL::GameFrame. 15 CTG matches per build (ntre_transit_ctg, ntre_rise_ctg, ntre_threadplate_ctg, one per ghost spawn), 30 bots, 1 round, builds interleaved:

	master	this PR
ComputePoseParam_MoveYaw, per call	9.6 us	0.44 us
its share of server game frame time	16.9 %	0.9 %
server game frame time	1.01 ms	0.86 ms (paired -13.6 %, 95 % CI +-7.0)

A perf profile of the same setup on an earlier master (0707264) put ConVarRef::ConVarRef / CCvar::FindVar under ComputePoseParam_MoveYaw at 13.8-16.4 % of server CPU. The client compiles and runs the same code per frame per player; it was built but not timed.

All 30 matches ended normally with no asserts, and 3 matches on a Debug build (one per map, 30 bots) had no asserts.

[AdamTadeusz]

wowee like +50 fps on isolation with 22 bots

(edit) well the fps counter is difficult to read, 50 fps might be a bit much but definitely a significant improvement

[AdamTadeusz]

also no ifdef NEOs, but I understand this is a draft pr and imagine you will want to move this into neoplayeranimstate anyway

[sunzenshen]

#2244 might actually accomplish the same and better than this, so waiting of the result of that review before deciding what to do with this PR.

(This PR edits hl2mp_playeranimstate.*, which #2244 no longer uses and could even remove from the build.)