Re: My Benchmark (was: looking for a better idiom)
[
Date Prev][
Date Next][
Thread Prev][
Thread Next]
[
Date Index]
[
Thread Index]
- Subject: Re: My Benchmark (was: looking for a better idiom)
- From: J.Jørgen von Bargen <jjvb.primus@...>
- Date: Thu, 9 Sep 2010 15:31:31 +0000 (UTC)
Scott Vokes <vokes.s <at> gmail.com> writes:
> luasocket's gettime() function may work better as a portable,
> reasonably high-precision timing function. I've used it for
> benchmarking on Windows, BSD, and Linux. "Battery" distributions like
> Lua for Windows tend to already have luasocket.
But (at least on windows) socket.gettime() is by far not high-resolution enough
Check this:
local hrt=require"HiResTimer"
local socket=require"socket"
local function printf(...)
io.write(string.format(...))
end
for loops=0,100000,1000 do
printf("%6d loops ",loops)
local t0=hrt.clock()
for i=1,loops do local j=math.sin(123) end
local t1=hrt.clock()
printf("hrt=%9.3f ms",(t1-t0)*1000)
local t0=socket.gettime()
for i=1,loops do local j=math.sin(123) end
local t1=socket.gettime()
printf(" socket=%9.3f ms\n",(t1-t0)*1000)
end
Result (truncated)
0 loops hrt= 0.035 ms socket= 0.000 ms
1000 loops hrt= 0.327 ms socket= 0.000 ms
2000 loops hrt= 0.461 ms socket= 0.000 ms
3000 loops hrt= 0.685 ms socket= 0.000 ms
4000 loops hrt= 0.905 ms socket= 0.000 ms
5000 loops hrt= 1.123 ms socket= 0.000 ms
6000 loops hrt= 1.391 ms socket= 0.000 ms
7000 loops hrt= 1.565 ms socket= 0.000 ms
8000 loops hrt= 1.801 ms socket= 15.625 ms
9000 loops hrt= 2.032 ms socket= 0.000 ms
10000 loops hrt= 2.244 ms socket= 0.000 ms
:::::
90000 loops hrt= 22.061 ms socket= 15.625 ms
91000 loops hrt= 20.248 ms socket= 31.250 ms
92000 loops hrt= 22.713 ms socket= 15.625 ms
93000 loops hrt= 22.575 ms socket= 15.625 ms
94000 loops hrt= 21.200 ms socket= 15.625 ms
95000 loops hrt= 22.974 ms socket= 15.625 ms
96000 loops hrt= 21.370 ms socket= 31.250 ms
97000 loops hrt= 23.359 ms socket= 31.250 ms
98000 loops hrt= 21.953 ms socket= 15.625 ms
99000 loops hrt= 22.304 ms socket= 15.625 ms
100000 loops hrt= 22.887 ms socket= 15.625 ms
socket has (again at least on windows) a resolution of 64 ticks/second,
the PerformanceCounter used in HiResTimer about 3500000 ticks/second
(will vary with the machine your running on)
So I can use 10000 loops to get significant comparable results with hrt,
but need at least 50000000 (!) loops with socket to get near the same
number of ticks.
Regards Jørgen