Here is my version, I switched to measuring nano seconds to get numbers
different from 0:
# Compile and run with 'nim c -r -d:useRealtimeGC -d:release main.nim'
import strutils
#import times
include "$lib/system/timers"
const
windowSize = 200000
msgCount = 1000000
type
Msg = seq[byte]
Buffer = seq[Msg]
var worst: Nanos
proc mkMessage(n: int): Msg =
result = newSeq[byte](1024)
for i in 0 .. <result.len:
result[i] = byte(n)
proc pushMsg(b: var Buffer, highID: int) =
let start = getTicks()
let m = mkMessage(highID)
# seqs copy, we don't want a copy here, so I used 'shallowCopy'.
# Alternatively the 'ref array' version could be used.
# Note that due to Nim's design we could also *re-use* the memory
# completely, eliminating the GC runs but this would make this
# benchmark pointless.
shallowCopy(b[highID mod windowSize], m)
GC_step(500) # 0.5ms, but GC never takes this long.
let elapsed = getTicks() - start
if elapsed > worst:
worst = elapsed
proc main() =
GC_disable()
# The MS backup collector is only required for cylic data structures,
# but in this program we generate no cycles. Nim allows us to specify this
# behaviour directly, so IMO it's fair to disable it. Nim's GC docs also
# mention this fact, it's not undocumented voodoo:
GC_disableMarkAndSweep()
var b = newSeq[Msg](windowSize)
for i in 0 .. <msgCount:
pushMsg(b, i)
# nano seconds into ms:
echo("Worst push time: ", worst, "nano seconds")
echo(GC_getStatistics())
when isMainModule:
main()
On my machine I get to roughly 23000 nano seconds.
Take with a big grain of salt!
* Read my comments in the code.
* I am not sure if "lib/system/timers" is reliable.
* I have a fast CPU. :)
