Messages in this thread | | | Date | Fri, 13 Jun 2014 15:28:58 -0600 | From | Jens Axboe <> | Subject | Re: [PATCH v7] NVMe: conversion to blk-mq |
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On 06/13/2014 01:22 PM, Keith Busch wrote: > One performance oddity we observe is that servicing the interrupt on the > thread sibling of the core that submitted the I/O is the worst performing > cpu you can chose; it's actually better to use a different core on the > same node. At least that's true as long as you're not utilizing the cpus > for other work, so YMMV.
This doesn't match what I see here. Just ran some test cases - both sync, and higher QD. For sync performance, core or thread sibling is the best choice, other CPUs next. That is pretty logical.
For a more loaded run, thread sibling ends up being a better choice than core, since core runs out of steam (255K vs 275K here). And thread sibling is still a marginally better choice than some other core on the same node.
Which pretty much matches my expectations of what the best mappings would be.
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