Show pageOld revisionsBacklinksBack to top This page is read only. You can view the source, but not change it. Ask your administrator if you think this is wrong. ====== PEBS disabled due to CPU errata ====== I noticed this in /var/log/messages on my freshly installed CentOS 7.5 system. <code> May 24 09:46:43 localhost kernel: smpboot: CPU0: Intel(R) Xeon(R) CPU E31220 @ 3.10GHz (fam: 06, model: 2a, stepping: 07) May 24 09:46:43 localhost kernel: Performance Events: PEBS fmt1+, 16-deep LBR, SandyBridge events, full-width counters, Intel PMU driver. May 24 09:46:43 localhost kernel: core: PEBS disabled due to CPU errata, please upgrade microcode May 24 09:46:43 localhost kernel: ... version: 3 May 24 09:46:43 localhost kernel: ... bit width: 48 May 24 09:46:43 localhost kernel: ... generic registers: 8 May 24 09:46:43 localhost kernel: ... value mask: 0000ffffffffffff May 24 09:46:43 localhost kernel: ... max period: 00007fffffffffff May 24 09:46:43 localhost kernel: ... fixed-purpose events: 3 May 24 09:46:43 localhost kernel: ... event mask: 00000007000000ff </code> RedHat has this to say about it. ref: https://access.redhat.com/solutions/634443 Root Cause * Clovertown and SandyBridge processors have errata regarding PEBS functionality. Diagnostic Steps * Look at /proc/cpuinfo for model number 15, 42 or 45 So I did <code> processor : 3 vendor_id : GenuineIntel cpu family : 6 model : 42 model name : Intel(R) Xeon(R) CPU E31220 @ 3.10GHz stepping : 7 microcode : 0x29 cpu MHz : 1599.951 cache size : 8192 KB </code> Install a few packages <code> # yum install microcode_ctl.x86_64 # yum install iucode-tool # reboot </code> I see this in /var/log/messages on the reboot <code> May 26 18:55:50 wine kernel: microcode: microcode updated early to revision 0x2d, date = 2018-02-07 </code> Confirmation the processor has microcode patches applied <code> processor : 3 vendor_id : GenuineIntel cpu family : 6 model : 42 model name : Intel(R) Xeon(R) CPU E31220 @ 3.10GHz stepping : 7 microcode : 0x2d </code> The microcode is being updated as the system loads. {{tag>microcode}} ~~LINKBACK~~ blog/pebs_disabled_due_to_cpu_errata.txt Last modified: 2018/05/26 19:05by brett