SparklyPaperMC/sparklypaper-server/minecraft-patches/sources/net/minecraft/server/level/ServerEntity.java.patch

--- a/net/minecraft/server/level/ServerEntity.java
+++ b/net/minecraft/server/level/ServerEntity.java
@@ -209,6 +_,7 @@
 
                 if (this.entity.hasImpulse || this.trackDelta || this.entity instanceof LivingEntity && ((LivingEntity)this.entity).isFallFlying()) {
                     Vec3 deltaMovement = this.entity.getDeltaMovement();
+                    if (deltaMovement != this.lastSentMovement) { // SparklyPaper start - skip distanceToSqr call in ServerEntity#sendChanges if the delta movement hasn't changed
                     double d = deltaMovement.distanceToSqr(this.lastSentMovement);
                     if (d > 1.0E-7 || d > 0.0 && deltaMovement.lengthSqr() == 0.0) {
                         this.lastSentMovement = deltaMovement;
@@ -226,6 +_,7 @@
                             this.broadcast.accept(new ClientboundSetEntityMotionPacket(this.entity.getId(), this.lastSentMovement));
                         }
                     }
+                    } // SparklyPaper end
                 }
 
                 if (packet != null) {