Comment 1:

I think last time this came up, we assumed it was a GC that ran during the test being
measured, but we've already forced a GC here before measurement:
In itoa_test.go:
func numAllocations(f func()) int {
        runtime.GC()
        memstats := new(runtime.MemStats)
        runtime.ReadMemStats(memstats)
        n0 := memstats.Mallocs
        f()
        runtime.ReadMemStats(memstats)
        return int(memstats.Mallocs - n0)
}

Comment 2:

This is a bad way to count allocations either way.
Maybe it is memory profiling, which does its own
allocations.  Package fmt's TestCountMallocs is
the right way to do it.

Comment 3:

This issue was closed by revision 84ef97b.

Status changed to Fixed.