Ubuntu Server 20.04 CPU Security Mitigation Performance Impact

[phoronix]

Phoronix: Ubuntu Server 20.04 CPU Security Mitigation Performance Impact

Earlier this week I published new benchmarks looking at the desktop CPU security mitigation impact with Ubuntu 20.04. Here are similar tests done in looking at the server mitigation impact with the near-final Ubuntu 20.04 LTS while testing server workloads on Intel Xeon and AMD EPYC server platforms. Like the desktop tests, the mitigation impact with the out-of-the-box protections against Spectre, Meltdown, and friends is being compared to booting the same Ubuntu 20.04 release with "mitigations=off" for run-time disabling of the relevant mitigations on each platform.

http://www.phoronix.com/vr.php?view=29090

[Spacefish]

Haswell / Broadwell generation benchmarks would be great, as such hardware is still used today!

[Michael]

Haswell / Broadwell generation benchmarks would be great, as such hardware is still used today!

There is the Haswell benchmark in the article.

[msroadkill612]

Just inexpertly saying, but re:

"the Xeon Scalable Skylake server saw a 11~12% hit as well, and the Xeon Scalable Cascade Lake Refresh with its hardware mitigations saw a 5% hit to the performance still from the out-of-the-box mitigations. The AMD EPYC Rome server with its hardware mitigations saw a 5% impact as well from this "mitigations=off" comparison focused on Ubuntu 20.04 Server."

OTOH, w/ Amd, there is no need to turn mitigations ON, afaict?

[Michael]

Just inexpertly saying, but re:

"the Xeon Scalable Skylake server saw a 11~12% hit as well, and the Xeon Scalable Cascade Lake Refresh with its hardware mitigations saw a 5% hit to the performance still from the out-of-the-box mitigations. The AMD EPYC Rome server with its hardware mitigations saw a 5% impact as well from this "mitigations=off" comparison focused on Ubuntu 20.04 Server."

OTOH, w/ Amd, there is no need to turn mitigations ON with AMD, afaict?

These are the default mitigations for where AMD is relevant/exposed (or where they otherwise apply a default on AMD CPUs). It was at defaults vs. all off, with not turning any extra "on".

[RussianNeuroMancer]

Did I missed KVM benchmarks?