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io_uring is faster than mmap

(www.bitflux.ai)
283 points ghuntley | 1 comments | 04 Sep 25 22:01 UTC | HN request time: 0s | source
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bawolff ◴[05 Sep 25 00:26 UTC] No.45133765[source]▶
Shouldn't you also compare to mmap with huge page option? My understanding is its presicely meant for this circumstance. I don't think its a fair comparison without it.

Respectfully, the title feels a little clickbaity to me. Both methods are still ultimately reading out of memory, they are just using different i/o methods.

replies(2): >>45134007 #>>45138806 #
1. mrlongroots ◴[05 Sep 25 14:09 UTC] No.45138806[source]▶
You don't need hugepages for basic 5GB/s sequential scans. I don't know the exact circumstances that would cause TLB pressure, but this is not it.

You can maybe reduce the number of page faults, but you can do that by walking the mapped address space once before the actual benchmark too.