PC Processors

[cyring]

As investigated, APERF and MPERF counters are messed up when Processor is resuming from S3

rdmsr -aX 0x000000e7
FFFFFFFFC0E01292
FFFFFFFFD3BFDE0D
FFFFFFFFC28CD6A6
FFFFFFFFC111C53A
FFFFFFFFC4B5D257
FFFFFFFFC1D4DC30
FFFFFFFFCA59D1F6
FFFFFFFFDF2B868A
...

The same happens consequently with the read-only counters: 0xc00000e7 and 0x000000e8

The obvious software fix would be to reset counters with a zero write

wrmsr -a 0x000000e7 0x0 ; wrmsr -a 0x000000e8 0x0

However instruction latency won't guarantee a perfect synchronization of all Cores' counters.

I would suggest AMD to fix this in a future microcode

Regards

CyrIng

[cyring · Accepted solution]

Resetting counters whilst the Resume function is a working solution. 

[cyring · Accepted solution]

Resetting counters whilst the Resume function is a working solution. 

[misterj · Accepted solution]

crying, this is a user forum and seldom do we see a AMDers here. I suggest you open an AMD Online Service request. Enjoy, John.