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Description of problem: The upstream --smi option of cyclictest helps to define if the worst-case latency is or is not caused by SMIs. I used it on a customer, so I think it is good to have it in the official build. Version-Release number of selected component (if applicable): The last version of rt-tests does not have --smi option.
Created attachment 1133228 [details] backport of the feature cyclictest: SMI count/detection via MSR/SMI counter Use the MSR/SMI counter on Intel's processor to detect/count SMIs. It is based on turbostat's implementation. SMI counting is enabled via --smi argument. When enabled, and additional field is added on both regular and verbose ouput. On the regular output, a SMI column shows how many SMIs occurred on each CPU during cyclictest's execution. For example: policy: fifo: loadavg: 0.09 0.05 0.02 1/194 2288 T: 0 ( 2285) P:80 I:1000 C: 9975 Min: 2 Act: 3 Avg: 4 Max: 20831 SMI: 2 T: 1 ( 2286) P:80 I:1500 C: 6650 Min: 2 Act: 2 Avg: 5 Max: 19910 SMI: 2 T: 2 ( 2287) P:80 I:2000 C: 4987 Min: 2 Act: 2 Avg: 6 Max: 20811 SMI: 2 T: 3 ( 2288) P:80 I:2500 C: 3990 Min: 2 Act: 3 Avg: 7 Max: 20322 SMI: 2 On verbose output, the last column shows how many SMIs occurred on each loop. For example: [ CPU | Loop | Lat | SMIs ] 0: 2156: 2 0 0: 2157: 2 0 0: 2158: 2 0 0: 2159: 20981 2 1: 1433: 2 0 1: 1434: 2 0 1: 1435: 2 0 1: 1436: 3 0 1: 1437: 2 0 1: 1438: 2 0 1: 1439: 20249 2 Signed-off-by: Daniel Bristot de Oliveira <bristot> Signed-off-by: John Kacur <jkacur>
Created attachment 1133229 [details] backport of man description of --smi option cyclictest: Add --smi description on cyclictest man page Add the description of the --smi command line option of cyclictest. "--smi Enable SMI count/detection on processors with SMI count support." Signed-off-by: Daniel Bristot de Oliveira <bristot> Signed-off-by: John Kacur <jkacur>
Brewbuild with the smi.patch: https://brewweb.devel.redhat.com/taskinfo?taskID=10603781
This was added in v0.97, so fixed earlier, but fixed at least in rt-tests-1.0-1.el7 and up
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://rhn.redhat.com/errata/RHBA-2016-2391.html