On Thu, Jul 27, 2023 at 9:19 AM Uwe Schindler <u...@thetaphi.de> wrote:
See Shipilevs blog: > https://shipilev.net/jvm/anatomy-quarks/30-conditional-moves/ > Really interesting! This is an awesome, quick explanation of the tradeoff CMOV is making (pre-computing both paths) vs branching (have to predict, with high cost of mis-prediction). Maybe priority queues (used heavily in Lucene, e.g. during disjunctive search, merging of terms during indexing or by MultiTerms at search time, etc.) are a possible place where the branch is hard to predict (on up or down heaping) and maybe CMOV could help? He also has some examples and also there's a command line option to tell > hotspot when to use cmov: -XX:ConditionalMoveLimit > Yay! Another fun JVM command-line flag to tweak :) Mike McCandless http://blog.mikemccandless.com
