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Jason Brown commented on CASSANDRA-13034: ----------------------------------------- As the patch is basically just the mechanics of switching to {{FastThreadLocal}} / {{FastThreadLocalThread}}, lgtm. +1 > Move to FastThreadLocalThread and FastThreadLocal > ------------------------------------------------- > > Key: CASSANDRA-13034 > URL: https://issues.apache.org/jira/browse/CASSANDRA-13034 > Project: Cassandra > Issue Type: Bug > Reporter: Robert Stupp > Assignee: Robert Stupp > Fix For: 3.x > > > (Supersedes/includes CASSANDRA-13033 for 3.X & trunk) > We still use {{ThreadLocal}} in a couple of places, so I was curious how much > faster {{FastThreadLocal}} is compared to {{ThreadLocal}}. A micro bench > tells, that {{FastThreadLocal}} has a runtime of ~2.7ns and {{ThreadLocal}} > of ~4.7ns - about 2ns slower (EDIT: subtracted baseline). > However, looking at the implementations it seems that {{ThreadLocal}} has > more dependent pointer gets than {{FastThreadLocal}}. This (CPU cache misses) > is not reflected in the artificial benchmark below. > The patch migrates all {{Thread}} instances (except a few in tests) and all > {{ThreadLocal}} instances. > {code:title=FastThreadLocalBench with 4 threads on 4 core CPU} > [java] FastThreadLocalBench.baseline 2 avgt 5 > 3.023 ± 0.081 ns/op > [java] FastThreadLocalBench.fastThreadLocal 2 avgt 5 > 5.610 ± 0.154 ns/op > [java] FastThreadLocalBench.fastThreadLocal 4 avgt 5 > 5.653 ± 0.042 ns/op > [java] FastThreadLocalBench.fastThreadLocal 8 avgt 5 > 5.763 ± 0.588 ns/op > [java] FastThreadLocalBench.fastThreadLocal 12 avgt 5 > 5.673 ± 0.117 ns/op > [java] FastThreadLocalBench.threadLocal 2 avgt 5 > 7.708 ± 0.723 ns/op > [java] FastThreadLocalBench.threadLocal 4 avgt 5 > 7.604 ± 0.059 ns/op > [java] FastThreadLocalBench.threadLocal 8 avgt 5 > 7.629 ± 0.080 ns/op > [java] FastThreadLocalBench.threadLocal 12 avgt 5 > 7.858 ± 0.483 ns/op > {code} -- This message was sent by Atlassian JIRA (v6.3.4#6332)