AMD 4th Gen EPYC "Genoa" To Enjoy Slightly Better Performance With Linux 6.3

Written by Michael Larabel in Software on 10 January 2023. Page 4 of 4. 4 Comments
Stress-NG: Test: NUMA
Stress-NG: Test: Mutex
Stress-NG: Test: Malloc
Stress-NG: Test: Forking
Stress-NG: Test: SENDFILE

To no surprise in the kernel micro-benchmarks there was a difference with Automatic IBRS support.

Apache Cassandra: Test: Writes
RocksDB: Test: Random Fill
nginx: Connections: 500

AMD 4th Gen EPYC already has been delivering fabulous performance under Linux as shown in many Phoronix articles over the past two months while now with Automatic IBRS on its way to the mainline kernel, there is another added "oomph" in some areas to squeeze slightly better performance out of the system. Though ideally it would have been nice to see Automatic IBRS support already lined up for the Linux kernel ahead of AMD launching Zen 4 processors in 2022.

AMD EPYC Genoa Auto IBRS Benchmark

In areas affected by Retpolines overhead, switching over to Auto IBRS as will be the default for Zen 4 CPUs once merged -- again, expected for Linux 6.3 -- can help the AMD 4th Gen EPYC servers achieve a few percent higher performance in areas like PostgreSQL, WireGuard and other networking operations, some OpenJDK Java workloads, Nginx, and more. Intel for their part has already been providing Enhanced IBRS (eIBRS) -- similar to AMD Automatic IBRS -- with their processors to avoid the Retpoline mitigation costs.

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Michael Larabel

Michael Larabel is the principal author of and founded the site in 2004 with a focus on enriching the Linux hardware experience. Michael has written more than 20,000 articles covering the state of Linux hardware support, Linux performance, graphics drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and automated benchmarking software. He can be followed via Twitter, LinkedIn, or contacted via