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config-linux: add schemata field to IntelRdt #1230

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30 changes: 21 additions & 9 deletions config-linux.md
Original file line number Diff line number Diff line change
Expand Up @@ -645,6 +645,7 @@ The following parameters can be specified for the container:
The value SHOULD start with `L3:` and SHOULD NOT contain newlines.
* **`memBwSchema`** *(string, OPTIONAL)* - specifies the schema of memory bandwidth per L3 cache id.
The value MUST start with `MB:` and MUST NOT contain newlines.
* **`schemata`** *(array of strings, OPTIONAL)* - specifies the schemata to be written to the `schemata` file in resctrlfs. Each element represents one line in the `schemata` file. The value MUST NOT contain newlines.

The following rules on parameters MUST be applied:

Expand All @@ -654,15 +655,17 @@ The following rules on parameters MUST be applied:

* If either `l3CacheSchema` or `memBwSchema` is set, runtimes MUST write the value to the `schemata` file in the that sub-directory discussed in `closID`.

* If neither `l3CacheSchema` nor `memBwSchema` is set, runtimes MUST NOT write to `schemata` files in any `resctrl` pseudo-filesystems.
* If `schemata` field is set, runtimes MUST write the value to the `schemata` file in the that sub-directory discussed in `closID`. If also `l3CacheSchema` or `memBwSchema` is set the value of `schemata` field must be written last, after the values from `l3CacheSchema` and `memBwSchema` has been written.

* If none of `l3CacheSchema`, `memBwSchema` or `schemata` is set, runtimes MUST NOT write to `schemata` files in any `resctrl` pseudo-filesystems.

* If `closID` is not set, runtimes MUST use the container ID from [`start`](runtime.md#start) and create the `<container-id>` directory.

* If `closID` is set, `l3CacheSchema` and/or `memBwSchema` is set
* If `closID` is set, `l3CacheSchema` and/or `memBwSchema` and/or `schemata` is set
* if `closID` directory in a mounted `resctrl` pseudo-filesystem doesn't exist, the runtimes MUST create it.
* if `closID` directory in a mounted `resctrl` pseudo-filesystem exists, runtimes MUST compare `l3CacheSchema` and/or `memBwSchema` value with `schemata` file, and [generate an error](runtime.md#errors) if doesn't match.

* If `closID` is set, and neither of `l3CacheSchema` and `memBwSchema` are set, runtime MUST check if corresponding pre-configured directory `closID` is present in mounted `resctrl`. If such pre-configured directory `closID` exists, runtime MUST assign container to this `closID` and [generate an error](runtime.md#errors) if directory does not exist.
* If `closID` is set, and none of `l3CacheSchema`, `memBwSchema` or `schemata` are set, runtime MUST check if corresponding pre-configured directory `closID` is present in mounted `resctrl`. If such pre-configured directory `closID` exists, runtime MUST assign container to this `closID` and [generate an error](runtime.md#errors) if directory does not exist.

* **`enableCMT`** *(boolean, OPTIONAL)* - specifies if Intel RDT CMT should be enabled:
* CMT (Cache Monitoring Technology) supports monitoring of the last-level cache (LLC) occupancy
Expand All @@ -674,18 +677,27 @@ The following rules on parameters MUST be applied:

### Example

Consider a two-socket machine with two L3 caches where the default CBM is 0x7ff and the max CBM length is 11 bits,
and minimum memory bandwidth of 10% with a memory bandwidth granularity of 10%.
Consider a two-socket machine with:

- two L3 caches where the default CBM is 0x7ff (11 bits)
- eight L2 caches where the default CBM is 0xFF (8 bits)
- minimum memory bandwidth of 10% with a memory bandwidth granularity of 10%

Tasks inside the container:

Tasks inside the container only have access to the "upper" 7/11 of L3 cache on socket 0 and the "lower" 5/11 L3 cache on socket 1,
and may use a maximum memory bandwidth of 20% on socket 0 and 70% on socket 1.
- have access to the "upper" 7/11 of L3 cache on socket 0 and the "lower" 5/11 L3 cache on socket 1
- have access to the "lower" 4/8 of L2 cache on socket 0 (socket 1 is left out from this example)
- may use a maximum memory bandwidth of 20% on socket 0 and 70% on socket 1.

```json
"linux": {
"intelRdt": {
"closID": "guaranteed_group",
"l3CacheSchema": "L3:0=7f0;1=1f",
"memBwSchema": "MB:0=20;1=70"
"schemata": [
"L3:0=7f0;1=1f",
"L2:0=f;1=f;2=f;3=f",
"MB:0=20;1=70"
]
}
}
```
Expand Down
5 changes: 4 additions & 1 deletion features-linux.md
Original file line number Diff line number Diff line change
Expand Up @@ -201,12 +201,15 @@ Irrelevant to the availability of SELinux on the host operating system.
Irrelevant to the availability of Intel RDT on the host operating system.

* **`enabled`** (bool, OPTIONAL) represents whether the runtime supports Intel RDT.
* **`schemata`** (bool, OPTIONAL) represents whether the
(`schemata` field of `linux.intelRdt` in `config.json`)[config-linux.md#intelrdt] is supported.

### Example

```json
"intelRdt": {
"enabled": true
"enabled": true,
"schemata": true
}
```

Expand Down
3 changes: 2 additions & 1 deletion features.md
Original file line number Diff line number Diff line change
Expand Up @@ -337,7 +337,8 @@ Here is a full example for reference.
"enabled": true
},
"intelRdt": {
"enabled": true
"enabled": true,
"schemata": true
}
},
"annotations": {
Expand Down
3 changes: 3 additions & 0 deletions schema/config-linux.json
Original file line number Diff line number Diff line change
Expand Up @@ -262,6 +262,9 @@
"closID": {
"type": "string"
},
"schemata": {
"$ref": "defs.json#/definitions/ArrayOfStrings"
},
"l3CacheSchema": {
"type": "string"
},
Expand Down
9 changes: 9 additions & 0 deletions specs-go/config.go
Original file line number Diff line number Diff line change
Expand Up @@ -795,14 +795,23 @@ type LinuxSyscall struct {
type LinuxIntelRdt struct {
// The identity for RDT Class of Service
ClosID string `json:"closID,omitempty"`

// Schemata specifies the complete schemata to be written as is to the
// schemata file in resctrl fs. Each element represents a single line in the schemata file.
// NOTE: This will overwrite schemas specified in the L3CacheSchema and/or
// MemBwSchema fields.
Schemata []string `json:"schemata,omitempty"`

// The schema for L3 cache id and capacity bitmask (CBM)
// Format: "L3:<cache_id0>=<cbm0>;<cache_id1>=<cbm1>;..."
// NOTE: Should not be specified if Schemata is non-empty.
L3CacheSchema string `json:"l3CacheSchema,omitempty"`

// The schema of memory bandwidth per L3 cache id
// Format: "MB:<cache_id0>=bandwidth0;<cache_id1>=bandwidth1;..."
// The unit of memory bandwidth is specified in "percentages" by
// default, and in "MBps" if MBA Software Controller is enabled.
// NOTE: Should not be specified if Schemata is non-empty.
MemBwSchema string `json:"memBwSchema,omitempty"`

// EnableCMT is the flag to indicate if the Intel RDT CMT is enabled. CMT (Cache Monitoring Technology) supports monitoring of
Expand Down
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