Messages in this thread | | | Date | Fri, 9 Sep 2022 15:18:40 +0200 | From | Peter Zijlstra <> | Subject | Re: Performance Regression in Linux Kernel 5.19 |
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On Fri, Sep 09, 2022 at 11:46:08AM +0000, Manikandan Jagatheesan wrote: > 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%) > > After performing the bisect between kernel 5.18 and 5.19, we > identified the root cause to be the enablement of IBRS mitigation > for spectre_v2 vulnerability by commit 6ad0ad2bf8a6 ("x86/bugs: > Report Intel retbleed vulnerability"). > > To confirm this, we have disabled the above security mitigation > through kernel boot parameter(spectre_v2=off) in 5.19 and re-ran > our tests & confirmed that the performance was on-par with > 5.18 release.
Well, duh.. :-)
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