Selectors in commands cause a lot of lag in 1.10

Partner Rank:

2

Partner Team Reporting:

Spark Squared

Verification builds:

1.10.0, Windows 10

Summary:

Selectors in commands cause a lot of lag in 1.10

Impact:

One of our maps is unplayable because of that issue: The game is slowed down by a factor of 2 to 4 (that factor varies randomly)

Repro Steps:

1. Create a flat world in 1.10
2. Summon 256 armor stands in the world (first summon one, then do
   /execute @e[type=armor_stand] ~ ~ ~ /summon armor_stand
   8 times)
3. Place 50 chain command blocks with this command:
   /testfor @e
4. Place a repeating command block in front of the chain and have it trigger the chain every tick.

Observed Results:

The tick rate drops to around 11 TPS (ticks per second), sometimes even lower, especially if the player is moving around instead of being static

Expected Results:

The tick rate should still be 20 TPS

Screenshots/Videos attached: Yes/No

No

Regression Builds:

1.9.5, Windows 10

Notes:

Creating the same mechanism in 1.9.5 doesn’t change the TPS much, it might drop from 20 to 19 sometimes.