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Ken Giusti updated DISPATCH-2000: --------------------------------- Priority: Critical (was: Major) > Consider increasing default internal buffer size > ------------------------------------------------ > > Key: DISPATCH-2000 > URL: https://issues.apache.org/jira/browse/DISPATCH-2000 > Project: Qpid Dispatch > Issue Type: Improvement > Components: Router Node > Affects Versions: 1.15.0 > Reporter: Charles E. Rolke > Priority: Critical > > Tests with the TCP adaptor and a 4k-byte buffer size show _significant > throughput increases_ with _otherwise minimal code changes_. For this > discussion, assume that the new buffer size will be 4k bytes. > Note: This discussion nearly parallels the discussion of increasing hard > drive sector size to 4K. See [Transition to Advanced Format 4K Sector Hard > Drives > |[https://www.seagate.com/tech-insights/advanced-format-4k-sector-hard-drives-master-ti/].] > The pros and cons of increasing the size for disk drives and for > qpid-dispatch are pretty much the same. > Dispatch has never had anything but 512-byte internal buffers. This lends a > lot of weight for keeping the current setting. However, from day one the self > tests exercise various buffer sizes from 1-byte to 10000-bytes and the tests > have worked fine. This is a positive indication that physically the buffer > functions and buffer management proper would work with any buffer size. > Logically there are some other issues. These must be understood and > considered before moving forward with any change. > * Expect total memory usage to go up due to unused buffer space with small > messages > * Expect total memory usage to go down due to more efficient buffer use with > large messages > * Policy implements Q2 throttling with a buffer count limit. If that limit > is not adjusted then flow control will not take effect until 8x as much AMQP > session data has been buffered. > Adjusting the buffer size from 512 to 4096 must happen either at compile time > or at run time very early, before qd_router_setup_late() is called, when > buffers start being created and buffer size cannot be changed any more. A > pull request is in the works that adds a --4k-buffer switch to the command > line to simplify testing with the larger buffer size. > I expect that going to 4K buffers will have a performance improvement > certainly for the TCP adaptor but also for the other protocol adaptors and > for AMQP as well. -- This message was sent by Atlassian Jira (v8.3.4#803005) --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@qpid.apache.org For additional commands, e-mail: dev-h...@qpid.apache.org