Throttling memory bandwidth via iMC on Intel(R) Xeon(R) CPU E5-2650 v3

[Wei_C_]

hi all,

I am trying memory throttling iMC feature on E5 v3 CPU. But I had some confusion and it did not work out yet.

Here is the lspci of my server:

.....

_{ff:14.0 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 Integrated Memory Controller 0 Channel 0 Thermal Control (rev 02)
ff:14.1 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 Integrated Memory Controller 0 Channel 1 Thermal Control (rev 02)}

_{ff:17.0 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 Integrated Memory Controller 1 Channel 0 Thermal Control (rev 02)}

_{ff:17.1 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 Integrated Memory Controller 1 Channel 1 Thermal Control (rev 02)}

...

Based on the Intel datasheet, I found this may help:

2.4.2  chn_temp_cfg which gives a offset of 0x108, inside they have:

27:27 RW 0x1 Enables thermal bandwidth throttling limit (bw_limit_thrt_en):

10:0   RW 0x3ff BW_LIMIT_TF (bw_limit_tf): BW Throttle Window Size in DCLK. Note: This value is left shifted 3 bits before being used

However, when I execute, setpci -s ff:17.0 0x108l, then I get:

ffffffff

And also, lspci -s ff:17.0 -xxx, I got

00: 86 80 1d 2f 00 00 00 00 02 00 80 08 00 00 80 00
10: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
20: 00 00 00 00 00 00 00 00 00 00 00 00 86 80 1d 2f
30: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
40: 00 00 00 00 c7 c2 b8 21 04 00 00 00 00 00 00 00
50: 00 30 00 00 00 00 00 00 00 00 00 00 00 00 00 00
60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
a0: 00 00 00 00 00 00 00 00 c0 66 00 00 00 00 00 00
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

Clearly, it did not make any sense based on the data sheet except the VID which is 2f1d. Can anyone help me to make this memory throttling work ?

Thanks!

Wei