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jaypipes / ghw

Go HardWare discovery/inspection library
Apache License 2.0
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begin work of supporting current resource usage #358

Open jaypipes opened 7 months ago

jaypipes commented 7 months ago

This patch begins the process of supporting current resource usage information in ghw. The first resource we support is memory on Linux systems.

Users can use the ghw.WithCollectUsage(true) function to instruct ghw to gather usage information for the module in question. Alternately, users can use the GHW_COLLECT_USAGE=1 environs variable. The following shows the effect of the variable:

jaypipes@lappie:~/src/github.com/jaypipes/ghw$ go run cmd/ghwc/main.go memory
memory (16GB physical, 16GB usable)
jaypipes@lappie:~/src/github.com/jaypipes/ghw$ GHW_COLLECT_USAGE=1 go run cmd/ghwc/main.go memory
memory (16GB physical, 16GB usable, 9GB used)

Issue #357

jaypipes commented 7 months ago

At glance, looks fine. The one and only reservation I have is that I'm not a fan of optional fields which are filled only if a global flag is set. I think we could have a couple or more of these fields in the various subsystems. I'd consider an approach on which we add current resource usage in a more isolated way with respect the current return value. A very quick proposal could be to wrap the resource usage in substructs. I'll have a proper review shortly in few days time tops.

@ffromani Hi! :)

Yeah, I had a similar thought and actually originally I had an approach where I had a separate Usage struct for each module (to go along with the Info structs in the modules. But eventually I just thought it would be more straightforward to add the fields to the main Info structs themselves.

For things like memory usage, we will always need to determine the structure (NUMA topology) of the system itself and then add usage per NUMA node (on Linux via /sys/devices/system/node/nodeX/meminfo) so we are always going to need to grab the Info structs... so I thought it easier to just add usage fields to the Info structs themselves... that way, we don't need to do any alternate JSON/YAML serialization or all the plumbing for the Info.load() methods...

jaypipes commented 7 months ago

@ffromani we could also consider collecting usage information by default and making the collection of usage information disable-able via flag?