Performance issues of running ES on Linux kernels patched for Meltdown/Spectre side channel attacks


(Øystein Larsen) #1

By now, of course, most of us are familiar with the side channel attacks disclosed yesterday detailed in https://meltdownattack.com/

Fixes to mitigate this are rolling out as we speak, with the Red Hat ecosystem having patched kernel packages available and Debian no doubt being close behind. Very superficially described, these kernel patches changes the way the kernel behaves when interacting with userland processes. As a result, a performance impact is expected, with the much-circulated estimate of anywhere between 5% and 30% performance reduction, depending on how the process in question works its ways and how often it talks to the kernel.

A set of initial benchmarks are now available at https://www.phoronix.com/scan.php?page=article&item=linux-415-x86pti&num=2 and I must admit I am still at a loss here with regards to estimating the impact on the Elastic stack.

The main question is - how will this affect JVM applications? I am tempted to perform a test myself but I am pressed for time as of now.


(Evan Fraser) #2

I find this very concerning also. I expect it'll be more of a bottleneck if you ES systems are currently CPU bound, and less so if you are currently IO bound. It'll vary hugely based on your workload.

I will be running some benchmarks around this for our workloads but i'm uncertain on the timeframe.


(system) #3

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