Scope of IA32_PERF_FIXED_CTR_CTRL Register

[Samuel_M_1]

Does anyone know the scope of the MSR:

IA32_PERF_FIXED_CTR_CTRL

on SandyBridge? It is not listed in Table 35-11 of the Intel SDM Vol 3, where the scope of similar MSRs such as IA32_PERF_GLOBAL_CTRL is given.

[Patrick_F_Intel1]

The scope of the MSR is 'per hw thread'.

The MSR (38dh) is listed in table 35-2 as an architectural MSR but the scope isn't listed.

I'll check with the SDM owner to see if we can get the scope listed in the table.

Pat

[Samuel_M_1]

Thank you Patrick. 

[Bernard]

 Scope of IA32_FIXED_CTRx( starts at MSR addressing space 0x309) which is conrolled by IA32_PERF_FIXED_CTR_CTRL is per thread.

Moreover you can set 21 bit of IA32_PERFEVTSELx to enable counters on all logical processors thus mapping measurement to any thread which happens to be executed by logical processor.If bit 21 == 0 only specified in IA32_PERFEVTSELx logical processor's thread is measured.