Differences between lobstr::mem_used() & memuse::Sys.procmem()

[mitch-tanney-coterie]

I currently see differences in reported memory consumption between the following commands.

print(lobstr::mem_used())
print(memuse::Sys.procmem()$size)

The result from the memuse::Sys.procmem()$size command matches or is very close to the values I see in the RStudio Environment pane.

Therefore, what exactly is lobstr::mem_used() describing? I apologize in advance if I'm missing something obvious in the documentation, but I'm curious to know the differences between these commands.

[hadley]

Basically, mem_used() reports the memory that R tracks from inside the process, and I suspect what memuse and RStudio track are the memory usage of the entire process (as reported by the operating system).