Since installing Kernel 2.6.32-696.18.7.el6 (Spectre / Meltdown mitigation) on our Centos 6 HAProxy box, the CPU has gone from around 20% to 100%.
The box is dedicated to running HAProxy (along with keepalived) and is supporting a relatively low 3-400 conns/s at around 40mbps. Loadbalancing a handful of websites with SSL termination at HAProxy. The CPU usage starts of fairly normal but within a couple of hours is just stuck at 100%.
Although not the latest and greatest, the box is a reasonable spec Dell PE1950 III, with 2 x Xeon x5460 quad core processors at 3.16ghz, 16gb of ram and Intel gb nics.
This has been running flawlessly for a year or so prior to installing 2.6.32-696.18.7
Any other experiences / advice would be greatly appreciated, for now I’ll rollback the Kernel.