What: /sys/devices/uncore_iio_x/dieX
Date: February 2020
Contact: Alexander Antonov <alexander.antonov@linux.intel.com>
Description:
Each IIO stack (PCIe root port) has its own IIO PMON block, so
each dieX file (where X is die number) holds
"Segment:Root Bus"
for PCIe root port, which can be monitored by that IIO PMON
block.
For example, on 4-die Xeon platform with up to 6 IIO stacks per
die
and, therefore, 6 IIO PMON blocks per die, the mapping of
IIO PMON block 0 exposes as the following::
$ ls /sys/devices/uncore_iio_0/die*
-r--r--r-- /sys/devices/uncore_iio_0/die0
-r--r--r-- /sys/devices/uncore_iio_0/die1
-r--r--r-- /sys/devices/uncore_iio_0/die2
-r--r--r-- /sys/devices/uncore_iio_0/die3
$ tail /sys/devices/uncore_iio_0/die*
==> /sys/devices/uncore_iio_0/die0 <==
0000:00
==> /sys/devices/uncore_iio_0/die1 <==
0000:40
==> /sys/devices/uncore_iio_0/die2 <==
0000:80
==> /sys/devices/uncore_iio_0/die3 <==
0000:c0
Which means::
IIO PMU 0 on die 0 belongs to PCI RP on bus 0x00, domain 0x0000
IIO PMU 0 on die 1 belongs to PCI RP on bus 0x40, domain 0x0000
IIO PMU 0 on die 2 belongs to PCI RP on bus 0x80, domain 0x0000
IIO PMU 0 on die 3 belongs to PCI RP on bus 0xc0, domain 0x0000
What: /sys/devices/uncore_upi_x/dieX
Date: March 2022
Contact: Alexander Antonov <alexander.antonov@linux.intel.com>
Description:
Each /sys/devices/uncore_upi_X/dieY file holds
"upi_Z,die_W"
value that means UPI link number X on die Y is connected to UPI
link Z on die W
and this link between sockets can be monitored
by UPI PMON block.
For example, 4-die Sapphire Rapids platform has the following
UPI 0 topology::
# tail /sys/devices/uncore_upi_0/die*
==> /sys/devices/uncore_upi_0/die0 <==
upi_1,die_1
==> /sys/devices/uncore_upi_0/die1 <==
upi_0,die_3
==> /sys/devices/uncore_upi_0/die2 <==
upi_1,die_3
==> /sys/devices/uncore_upi_0/die3 <==
upi_0,die_1
Which means::
UPI link 0 on die 0 is connected to UPI link 1 on die 1
UPI link 0 on die 1 is connected to UPI link 0 on die 3
UPI link 0 on die 2 is connected to UPI link 1 on die 3
UPI link 0 on die 3 is connected to UPI link 0 on die 1
