OpenEuphoria

Strange benchmark result for Phix vs Eu 3.1.1

• Posted by lesterb Aug 21, 2017
• 1323 views

I was messing about with file benchmarks and came across a case where Phix is much slower than Eu 3.1. The benchmark requires 100 files to be created on disk, with each file containing 1000000 random bytes. The program for Eu is...

constant 
    BUFFER_SIZE = 10000, 
    SizeOfFile = 1000000, 
    FilesToWrite = 100, 
    randbuff = repeat(255, BUFFER_SIZE) 
 
integer cnt, fptr, blen 
atom tend, tstart 
tstart = time() 
 
for NFiles = 1 to FilesToWrite do 
    fptr = open(sprintf("f%d.dum", NFiles), "wb") 
    cnt = SizeOfFile 
    blen = BUFFER_SIZE 
 
    while cnt > 0 do 
        if cnt < blen then 
            blen = cnt 
        end if 
 
        puts(fptr, rand(randbuff[1..blen]))         -- EU 
        -- puts(fptr, sq_rand(randbuff[1..blen]))   -- PHIX 
        cnt -= blen 
    end while 
 
    close(fptr) 
end for 
 
tend = time() 
printf(1, "Execution time = %3.2f\n", tend - tstart) 

On my setup with Eu 3.1.1, this runs in about 5 sec. Very reasonable. With Phix 0.7.6 (change the rand call to sq_rand) it takes almost 13 sec. I have verified that it's the sq_rand call that makes the big difference by removing all the file stuff and just generating random data.

The sawn-off Eu benchmark code is...

constant 
    BUFFER_SIZE = 10000, 
    SizeOfFile = 1000000, 
    FilesToWrite = 100, 
    randbuff = repeat(255, BUFFER_SIZE) 
 
integer cnt, blen 
atom tend, tstart 
sequence p 
tstart = time() 
 
for NFiles = 1 to FilesToWrite do 
    cnt = SizeOfFile 
    blen = BUFFER_SIZE 
 
    while cnt > 0 do 
        if cnt < blen then 
            blen = cnt 
        end if 
 
        p = rand(randbuff[1..blen])         -- EU 
        -- p = sq_rand(randbuff[1..blen])   -- PHIX 
        cnt -= blen 
    end while 
end for 
 
tend = time() 
printf(1, "Execution time = %3.2f\n", tend - tstart) 

The timings are now Eu: 4.5 sec, Phix: 12.4 sec.

Since I know in this case that the random buffer has no nested sequences, I wrote my own function which avoids the nested call to sq_rand as follows...

function bsq_rand(object a) 
    for i = 1 to length(a) do 
        a[i] = rand(a[i]) 
    end for 
    return a 
end function 

Using bsq_rand instead of sq_rand in the code above gives Phix: 4.21 sec.

So I know how to improve the Phix benchmark result but it surprised me how big the difference in time is.

Is this related to the other discussion on function calling?