3543960689
switch to logrus for logging. replaced old logging library with a wrapper around logrus. We now just need to use the exported Log(...) and Logf(...) from the logging/ package that wraps around a set of loggers constituting a chain (following COR). Loggers are configured using a YAML file that specifies the following. 1. enabled/disabled 2. whether the message should be logged on console. 3. filename extension. 4. minimum log level. Retrofitted source code to now use the updated logging library. Updated the documentation with information regarding the specification of the log config file. Currently, the log format in the config file is not adhered to. This is going to be addressed in a future commit.
58 lines
3 KiB
Markdown
58 lines
3 KiB
Markdown
# Performance Co-Pilot (PCP) Data
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_Elektron_ makes use of PCP to collect performance metrics using the [pcp config](../../config) file.
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[pmdumptext](https://pcp.io/man/man1/pmdumptext.1.html) is used to retrieve all the data. The command used to retrieve the performance metrics is shown below (can also be found [here](https://gitlab.com/spdf/elektron/blob/master/pcp/pcp.go#L15)).
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```commandline
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pmdumptext -m -l -f '' -t 1.0 -d , -c <config file>
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```
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The logs are written to a file named _\<logFilePrefix\>\_\<timestamp\>.pcplog_, where
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* _logFilePrefix_ is the prefix provided using the `-logPrefix` option.
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* _timestamp_ corresponds to the time when _Elektron_ was run.
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Use `-pminfo` to obtain information about different performance metrics that can be monitored through Performance Co-Pilot. Please see [pminfo doc](https://pcp.io/man/man1/pminfo.1.html) for usage and options.
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#### Example PCP log
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Assume we want to retrieve the following performance metrics collected from one host, _myhost_.<br>
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* System CPU time
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* User CPU time
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Then the PCP config file would be as shown below.
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```
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myhost:kernel.all.cpu.user
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myhost:kernel.all.cpu.sys
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```
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When we run the `pmdumptext` command mentioned above for 5 seconds, the PCP log from _Elektron_ would be as shown below.
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```
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[<loglevel>]: <yyyy-mm-dd> <hh:mm:ss> myhost:kernel.all.cpu.user,myhost:kernel.all.cpu.sys
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[<loglevel>]: <yyyy-mm-dd> <hh:mm:ss> <myhost user cpu time>,<myhost system cpu time>
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[<loglevel>]: <yyyy-mm-dd> <hh:mm:ss> <myhost user cpu time>,<myhost system cpu time>
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[<loglevel>]: <yyyy-mm-dd> <hh:mm:ss> <myhost user cpu time>,<myhost system cpu time>
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[<loglevel>]: <yyyy-mm-dd> <hh:mm:ss> <myhost user cpu time>,<myhost system cpu time>
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[<loglevel>]: <yyyy-mm-dd> <hh:mm:ss> <myhost user cpu time>,<myhost system cpu time>
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```
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## Power Measurements
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It is also possible to measure the power consumption of CPU, DRAM etc., through the use of RAPL hardware counters.
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When running the power capping strategies, [Extrema](../PowerCappingStrategies.md) and [Progressive Extrema](../PowerCappingStrategies.md), the following performance metrics MUST be included in the PCP config file.
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```
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#RAPL CPU PKG
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<hostname1>:perfevent.hwcounters.rapl__RAPL_ENERGY_PKG.value
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<hostname2>:perfevent.hwcounters.rapl__RAPL_ENERGY_PKG.value
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...
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#RAPL DRAM
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<hostname1>:perfevent.hwcounters.rapl__RAPL_ENERGY_DRAM.value
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<hostname2>:perfevent.hwcounters.rapl__RAPL_ENERGY_DRAM.value
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...
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```
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Note that the power readings are retrieved for each processor on each worker node. For example, if you have two processors on a machine (hostname = _myhost_), then the PCP log for CPU and DRAM power readings would contain the following headers.
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`myhost:perfevent.hwcounters.rapl__RAPL_ENERGY_PKG.value["cpux"]`
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`myhost:perfevent.hwcounters.rapl__RAPL_ENERGY_PKG.value["cpuy"]`
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`myhost:perfevent.hwcounters.rapl__RAPL_ENERGY_DRAM.value["cpux"]`
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`myhost:perfevent.hwcounters.rapl__RAPL_ENERGY_DRAM.value["cpuy"]`
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Use `-pminfo` and search for RAPL to get the list of RAPL packages from which data can be read from.
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