• Austin Clements's avatar
    runtime: make next_gc ^0 when GC is disabled · fa9b57bb
    Austin Clements authored
    When GC is disabled, we set gcpercent to -1. However, we still use
    gcpercent to compute several values, such as next_gc and gc_trigger.
    These calculations are meaningless when gcpercent is -1 and result in
    meaningless values. This is okay in a sense because we also never use
    these values if gcpercent is -1, but they're confusing when exposed to
    the user, for example via MemStats or the execution trace. It's
    particularly unfortunate in the execution trace because it attempts to
    plot the underflowed value of next_gc, which scales all useful
    information in the heap row into oblivion.
    
    Fix this by making next_gc ^0 when gcpercent < 0. This has the
    advantage of being true in a way: next_gc is effectively infinite when
    gcpercent < 0. We can also detect this special value when updating the
    execution trace and report next_gc as 0 so it doesn't blow up the
    display of the heap line.
    
    Change-Id: I4f366e4451f8892a4908da7b2b6086bdc67ca9a9
    Reviewed-on: https://go-review.googlesource.com/30016Reviewed-by: default avatarRick Hudson <rlh@golang.org>
    fa9b57bb
mstats.go 21.5 KB