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Jonathan Ellis edited comment on CASSANDRA-3578 at 12/5/13 8:44 PM: -------------------------------------------------------------------- v3 logs average sync duration (for all syncs) and average overage (for just the laggy ones). think that's as good as we'll get without logging histograms :) was (Author: jbellis): v3 lags average sync duration (for all syncs) and average overage (for just the laggy ones). think that's as good as we'll get without logging histograms :) > Multithreaded commitlog > ----------------------- > > Key: CASSANDRA-3578 > URL: https://issues.apache.org/jira/browse/CASSANDRA-3578 > Project: Cassandra > Issue Type: Improvement > Reporter: Jonathan Ellis > Assignee: Benedict > Priority: Minor > Labels: performance > Fix For: 2.1 > > Attachments: 0001-CASSANDRA-3578.patch, 3578-logging-v2.txt, > 3578-logging-v3.txt, ComitlogStress.java, Current-CL.png, > Multi-Threded-CL.png, TestEA.java, latency.svg, oprate.svg, > parallel_commit_log_2.patch > > > Brian Aker pointed out a while ago that allowing multiple threads to modify > the commitlog simultaneously (reserving space for each with a CAS first, the > way we do in the SlabAllocator.Region.allocate) can improve performance, > since you're not bottlenecking on a single thread to do all the copying and > CRC computation. > Now that we use mmap'd CommitLog segments (CASSANDRA-3411) this becomes > doable. > (moved from CASSANDRA-622, which was getting a bit muddled.) -- This message was sent by Atlassian JIRA (v6.1#6144)