Slowdown when putting symbols into image data

[Alex Tweedly]

On 10/09/2014 00:17, Alex Tweedly wrote:
>  I'll go experiment ....
>
> -- Alex.
Experimenting with copying a block of bytes in 7.0.0 RC1

Script is included in its entirety below - but basically it creates a 
block of 1000 lines, 27K chars/bytes
It then repeatedly copies over a section of 104 bytes, or 104 chars or 4 
lines (i.e. 104 chars)

As expected, copying by line is slower than by char or byte, and becomes 
increasingly slower as we choose lines further into the data.

In 6.7 (DP1), the times to copy chars or bytes are equal and very small, 
while the number for lines is quite small.

In 7.0 RC1, the times are all *MUCH* larger  - to the point where I'd 
say 7.0 is unacceptable.
And in addition, copying bytes takes over twice as long as copying chars 
- when if anything it should be the other way round.

7.0 RC1
bytes took  313
chars took  137
lines took  4058

6.7 (DP4)
bytes took  8
chars took  8
lines took  411

i.e. 7.0 is 40 times slower for copying a block of data !!

I'll try to enter a bug report and when (if) I succeed, I'll post the 
number here.


-- Alex.

constant K = 10  -- which gives 2**10 lines of data
constant KSTART = 4 -- starting offset - large numbers should make lines 
slow, but not affect bytes
constant COUNT = 20000 -- make this big enough to get useful data

on mouseUp
    -- setup
    local tt, tStartData, cPos1, cPos2, t1, t2
    put "abcdefghijklmnopqrstuvwxyz" & CR into tt
    repeat K times
       put tt after tt
    end repeat

    put tt into tStartData
    put "data has" && the number of lines in tStartData && the number of 
bytes in tStartData &CR after fld 1

    put the number of chars in line 1 to KSTART of tStartData into cPos1
    put the number of chars in line 1 to kSTART + 4 of tStartData into cPos2

    put the millisecs into t1
    repeat COUNT times
       put byte 1 to cPos2 - cPos1 +1 of tt into byte cPos1 to cPos2 of 
tStartData
    end repeat
    put the millisecs into t2
    put "bytes took " && t2 - t1 &CR after msg

    put the millisecs into t1
    repeat COUNT times
       put char 1 to cPos2 - cPos1 +1 of tt into char cPos1 to cPos2 of 
tStartData
    end repeat
    put the millisecs into t2
    put "chars took " && t2 - t1 &CR after msg

    put the millisecs into t1
    repeat COUNT times
       put line KSTART to KSTART+4 of tt into line KSTART to KSTART+4 of 
tStartData
    end repeat
    put the millisecs into t2
    put "lines took " && t2 - t1 &CR after msg

end mouseUp