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config-linux: add Intel RDT/MBA Linux support
Add support for Intel Resource Director Technology (RDT) / Memory Bandwidth Allocation (MBA). Add memory bandwidth resource constraints in Linux-specific configuration. In this PR, the spec for memory bandwidth (memBwSchema) keeps the same format as existed spec for L3 cache (l3CacheSchema) for consistency and compatibility in runtime-spec 1.x. Example: "linux": { "intelRdt": { "l3CacheSchema": "L3:0=7f0;1=1f", "memBwSchema": "MB:0=20;1=70" } } This is the prerequisite of this runc proposal: opencontainers/runc#1596 For more information about Intel RDT/MBA, please refer to: opencontainers/runc#1596 Signed-off-by: Xiaochen Shen <[email protected]>
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‎config-linux.md‎

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@@ -461,24 +461,35 @@ The following parameters can be specified to set up the controller:
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If `intelRdt` is set, the runtime MUST write the container process ID to the `<container-id>/tasks` file in a mounted `resctrl` pseudo-filesystem, using the container ID from [`start`](runtime.md#start) and creating the `<container-id>` directory if necessary.
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If no mounted `resctrl` pseudo-filesystem is available in the [runtime mount namespace](glossary.md#runtime-namespace), the runtime MUST [generate an error](runtime.md#errors).
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If `intelRdt` is not set, the runtime MUST NOT manipulate any `resctrl` pseudo-filesystems.
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If `intelRdt` is not set, the runtime MUST NOT manipulate any `resctrl` pseudo-filesystems.
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The following parameters can be specified for the container:
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* **`l3CacheSchema`** *(string, OPTIONAL)* - specifies the schema for L3 cache id and capacity bitmask (CBM).
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If `l3CacheSchema` is set, runtimes MUST write the value to the `schemata` file in the `<container-id>` directory discussed in `intelRdt`.
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The value SHOULD start with `L3:` and SHOULD NOT contain newlines.
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* **`memBwSchema`** *(string, OPTIONAL)* - specifies the schema of memory bandwidth percentage per L3 cache id.
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The value MUST start with `MB:` and MUST NOT contain newlines.
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If `l3CacheSchema` is not set, runtimes MUST NOT write to `schemata` files in any `resctrl` pseudo-filesystems.
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If both `l3CacheSchema` and `memBwSchema` are set, runtimes MUST write the combined value to the `schemata` file in the `<container-id>` directory discussed in `intelRdt`.
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If `l3CacheSchema` contains a line beginning with `MB:`, the value written to `schemata` file MUST be the non-`MB:` line(s) from `l3CacheSchema` and the line from `memBWSchema`.
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If either `l3CacheSchema` or `memBwSchema` is set, runtimes MUST write the value to the `schemata` file in the `<container-id>` directory discussed in `intelRdt`.
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If neither `l3CacheSchema` nor `memBwSchema` is set, runtimes MUST NOT write to `schemata` files in any `resctrl` pseudo-filesystems.
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### Example
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Consider a two-socket machine with two L3 caches where the default CBM is 0xfffff and the max CBM length is 20 bits.
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Tasks inside the container only have access to the "upper" 80% of L3 cache id 0 and the "lower" 50% L3 cache id 1:
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Consider a two-socket machine with two L3 caches where the default CBM is 0x7ff and the max CBM length is 11 bits,
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and minimum memory bandwidth of 10% with a memory bandwidth granularity of 10%.
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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,
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and may use a maximum memory bandwidth of 20% on socket 0 and 70% on socket 1.
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```json
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"linux": {
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"intelRdt": {
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"l3CacheSchema": "L3:0=ffff0;1=3ff"
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"l3CacheSchema": "L3:0=7f0;1=1f",
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"memBwSchema": "MB:0=20;1=70"
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}
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}
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```

‎schema/config-linux.json‎

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"l3CacheSchema": {
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"id": "https://opencontainers.org/schema/bundle/linux/intelRdt/l3CacheSchema",
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"type": "string"
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},
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"memBwSchema": {
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"id": "https://opencontainers.org/schema/bundle/linux/intelRdt/memBwSchema",
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"type": "string",
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"pattern": "^MB:[^\\n]*$"
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}
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}
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}

‎specs-go/config.go‎

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@@ -158,8 +158,8 @@ type Linux struct {
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ReadonlyPaths []string `json:"readonlyPaths,omitempty"`
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// MountLabel specifies the selinux context for the mounts in the container.
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MountLabel string `json:"mountLabel,omitempty"`
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// IntelRdt contains Intel Resource Director Technology (RDT) information
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// for handling resource constraints (e.g., L3 cache) for the container
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// IntelRdt contains Intel Resource Director Technology (RDT) information for
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// handling resource constraints (e.g., L3 cache, memory bandwidth) for the container
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IntelRdt *LinuxIntelRdt `json:"intelRdt,omitempty"`
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}
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@@ -561,10 +561,14 @@ type LinuxSyscall struct {
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Args []LinuxSeccompArg `json:"args,omitempty"`
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}
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// LinuxIntelRdt has container runtime resource constraints
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// for Intel RDT/CAT which introduced in Linux 4.10 kernel
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// LinuxIntelRdt has container runtime resource constraints for Intel RDT
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// CAT and MBA features which introduced in Linux 4.10 and 4.12 kernel
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type LinuxIntelRdt struct {
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// The schema for L3 cache id and capacity bitmask (CBM)
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// Format: "L3:<cache_id0>=<cbm0>;<cache_id1>=<cbm1>;..."
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L3CacheSchema string `json:"l3CacheSchema,omitempty"`
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// The schema of memory bandwidth percentage per L3 cache id
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// Format: "MB:<cache_id0>=bandwidth0;<cache_id1>=bandwidth1;..."
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MemBwSchema string `json:"memBwSchema,omitempty"`
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}

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