cc-metric-collector/collectors/README.md

This folder contains the collectors for the cc-metric-collector.

metricCollector.go

The base class/configuration is located in metricCollector.go.

Collectors

• memstatMetric.go: Reads /proc/meminfo to calculate the node metric mem_used
• loadavgMetric.go: Reads /proc/loadavg and submits the node metrics:
  • load_one
  • load_five
  • load_fifteen
• netstatMetric.go: Reads /proc/net/dev and submits for all network devices (except loopback lo) the node metrics:
  • <dev>_bytes_in
  • <dev>_bytes_out
  • <dev>_pkts_in
  • <dev>_pkts_out
• lustreMetric.go: Reads Lustre's stats file /proc/fs/lustre/llite/lnec-XXXXXX/stats and submits the node metrics:
  • read_bytes
  • read_requests
  • write_bytes
  • write_bytes
  • open
  • close
  • getattr
  • setattr
  • statfs
  • inode_permission
• infinibandMetric.go: Reads InfiniBand LID from /sys/class/infiniband/mlx4_0/ports/1/lid and uses the perfquery command to read the node metrics:
  • ib_recv
  • ib_xmit
• likwidMetric.go: Reads hardware performance events using LIKWID. It submits socket and cpu metrics:
  • mem_bw (socket)
  • power (socket, Sum of RAPL domains PKG and DRAM)
  • flops_dp (cpu)
  • flops_sp (cpu)
  • flops_any (cpu, 2*flops_dp + flops_sp)
  • cpi (cpu)
  • clock (cpu)

LIKWID collector

Only the likwidMetric.go requires preparation steps. For this, the Makefile can be used. The LIKWID build needs to be configured:

• Version of LIKWID in LIKWID_VERSION
• Target user for LIKWID's accessdaemon in DAEMON_USER. The user has to have enough permissions to read the msr and pci device files
• Target group for LIKWID's accessdaemon in DAEMON_GROUP

It performs the following steps:

• Download LIKWID tarball
• Unpacking
• Adjusting configuration for LIKWID build
• Build it
• Copy all required files into collectors/likwid
• The accessdaemon is installed with the suid bit set using sudo also into collectors/likwid

Custom metrics for LIKWID

The likwidMetric.go collector uses it's own performance group tree by copying it from the LIKWID sources. By adding groups to this directory tree, you can use them in the collector. Additionally, you have to tell the collector which group to measure and which event count or derived metric should be used.

The collector contains a hash map with the groups and metrics (reduced set of metrics):

var likwid_metrics = map[string][]LikwidMetric{
	"MEM_DP": {LikwidMetric{name: "mem_bw", search: "Memory bandwidth [MBytes/s]", socket_scope: true}},
	"FLOPS_SP": {LikwidMetric{name: "clock", search: "Clock [MHz]", socket_scope: false}},
}

The collector will measure both groups MEM_DP and FLOPS_DP for duration seconds (global config.json). It matches the LIKWID name by using the search string and submits the value with the given name as field name in either the socket or the cpu metric depending on the socket_scope flag.

Todos

• Aggregate a per-hwthread metric to a socket metric if socket_scope=true
• Add a JSON configuration file likwid.json and suitable reader for the metrics and group tree path.
  • Do we need separate sections for CPU architectures? (one config file for all architectures?)
  • How to encode postprocessing steps. There are Go packages like eval or govaluate but they seem to be not maintained anymore.

Contributing own collectors

A collector reads data from any source, parses it to metrics and submits these metrics to the metric-collector. A collector provides three function:

• Init() error: Initializes the collector and its data structures.
• Read(duration time.Duration) error: Read, parse and submit data. If the collector has to measure anything for some duration, use the provided function argument duration
• Close(): Closes down the collector.

It is recommanded to call setup() in the Init() function as it creates the required data structures.

Each collector contains data structures for the submission of metrics after calling setup() in Init():

• node (map[string]string): Just key-value store for all metrics concerning the whole system
• sockets (map[int]map[string]string): One key-value store per CPU socket like sockets[1]["testmetric] = 1.0 for the second socket. You can either use len(sockets) to get the amount of sockets or you use SocketList().
• cpus (map[int]map[string]string): One key-value store per hardware thread like cpus[12]["testmetric] = 1.0. You can either use len(cpus) to get the amount of hardware threads or you use CpuList().