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Memory Bandwidth Allocation (MBA) is a resource allocation sub-feature of Intel Resource Director Technology (RDT) which is supported on some Intel Xeon platforms. Intel RDT/MBA provides indirect and approximate throttle over memory bandwidth for the software. A user controls the resource by indicating the percentage of maximum memory bandwidth. Hardware details of Intel RDT/MBA can be found in section 17.18 of Intel Software Developer Manual: https://software.intel.com/en-us/articles/intel-sdm In Linux 4.12 kernel and newer, Intel RDT/MBA is enabled by kernel config CONFIG_INTEL_RDT. If hardware support, CPU flags `rdt_a` and `mba` will be set in /proc/cpuinfo. Intel RDT "resource control" filesystem hierarchy: mount -t resctrl resctrl /sys/fs/resctrl tree /sys/fs/resctrl /sys/fs/resctrl/ |-- info | |-- L3 | | |-- cbm_mask | | |-- min_cbm_bits | | |-- num_closids | |-- MB | |-- bandwidth_gran | |-- delay_linear | |-- min_bandwidth | |-- num_closids |-- ... |-- schemata |-- tasks |-- <container_id> |-- ... |-- schemata |-- tasks For MBA support for `runc`, we will reuse the infrastructure and code base of Intel RDT/CAT which implemented in #1279. We could also make use of `tasks` and `schemata` configuration for memory bandwidth resource constraints. The file `tasks` has a list of tasks that belongs to this group (e.g., <container_id>" group). Tasks can be added to a group by writing the task ID to the "tasks" file (which will automatically remove them from the previous group to which they belonged). New tasks created by fork(2) and clone(2) are added to the same group as their parent. The file `schemata` has a list of all the resources available to this group. Each resource (L3 cache, memory bandwidth) has its own line and format. Memory bandwidth schema: It has allocation values for memory bandwidth on each socket, which contains L3 cache id and memory bandwidth percentage. Format: "MB:<cache_id0>=bandwidth0;<cache_id1>=bandwidth1;..." The minimum bandwidth percentage value for each CPU model is predefined and can be looked up through "info/MB/min_bandwidth". The bandwidth granularity that is allocated is also dependent on the CPU model and can be looked up at "info/MB/bandwidth_gran". The available bandwidth control steps are: min_bw + N * bw_gran. Intermediate values are rounded to the next control step available on the hardware. For more information about Intel RDT kernel interface: https://www.kernel.org/doc/Documentation/x86/intel_rdt_ui.txt An example for runc: Consider a two-socket machine with two L3 caches where the minimum memory bandwidth of 10% with a memory bandwidth granularity of 10%. Tasks inside the container may use a maximum memory bandwidth of 20% on socket 0 and 70% on socket 1. "linux": { "intelRdt": { "memBwSchema": "MB:0=20;1=70" } } Signed-off-by: Xiaochen Shen <xiaochen.shen@intel.com> |
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| rootless.go | ||
| rootless_test.go | ||
| validator.go | ||
| validator_test.go | ||