When SNC is enabled monitoring data is collected at the SNC node
granularity, but must be reported at L3-cache granularity for
backwards compatibility in addition to reporting at the node
level.
Add a "ci" field to the rdt_mon_domain structure to save the
cache information about the enclosing L3 cache for the domain.
This provides:
1) The cache id which is needed to compose the name of the legacy
monitoring directory, and to determine which domains should be
summed to provide L3-scoped data.
2) The shared_cpu_map which is needed to determine which CPUs can
be used to read the RMID counters with the MSR interface.
This is the first step to an eventual goal of monitor reporting files
like this (for a system with two SNC nodes per L3):
$ cd /sys/fs/resctrl/mon_data
$ tree mon_L3_00
mon_L3_00 <- 00 here is L3 cache id
├── llc_occupancy \ These files provide legacy support
├── mbm_local_bytes > for non-SNC aware monitor apps
├── mbm_total_bytes / that expect data at L3 cache level
├── mon_sub_L3_00 <- 00 here is SNC node id
│ ├── llc_occupancy \ These files are finer grained
│ ├── mbm_local_bytes > data from each SNC node
│ └── mbm_total_bytes /
└── mon_sub_L3_01
├── llc_occupancy \
├── mbm_local_bytes > As above, but for node 1.
└── mbm_total_bytes /
Signed-off-by: Tony Luck <tony.luck@xxxxxxxxx>
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