The latest Linux kernel update could play havoc with your VMs

Computing performance for Linux VMs running the latest kernel update could have seen a decrease of up to 70%, new figures have found.

Recent research by VMWare performance engineering staffer Manikandan Jagatheesan found running virtual machines with the Linux distro on the ESXi hypervisor, using the latest kernel update version 5.19, could see computing power reduce by more than two-thirds when using a single vCPU.

Further ripple effects were also found in networking, with a loss of almost one-third, and storage performance, which saw up to a decrease of around one in ten.

Linux 5.19 performance

The findings were posted to the Linux Kernel Mailing List (opens in new tab) on September 9 under a post entitled “Performance Regression in Linux Kernel 5.19”.

“As part of VMware’s performance regression testing for Linux Kernel upstream releases, we have evaluated the performance of Linux kernel 5.19 against the 5.18 release and we have noticed performance regressions in Linux VMs on ESXi as shown below.

– Compute(up to -70%)
– Networking(up to -30%)
– Storage(up to -13%)”

According to the analysis, the test were run on Intel Skylake CPUs, which The Register (opens in new tab) says many businesses are continuing to use today, despite being released between 2015 and 2017.

Jagatheesan said that VMWare’s testers had disabled Retbleed in version 5.19, which saw ESXi performance return to previous 5.18 levels. While companies can decide to follow this method to restore previous levels of performance, should they decide that the risk of deactivating Retbleed is too high, they will suffer up to a 70% reduction in performance, which could be unacceptable if not catastrophic for many business operations.

Linux creator Linus Torvalds has not commented on Jagatheesan’s post, which suggests that he does not appear too concerned about the news. This could be because progress for version 6.0 is well underway, with release candidate five available.