[REBOL] Rugby compressed vs. not compressed content delivery tests ...
From: petr::krenzelok::trz::cz at: 12-Feb-2002 9:51
Hi,
so I finally managed to find out how to turn off default compression of
Rugby. As Maarten stated - new Rugby core uses compression for all
content delivery. From my experience I know that compressing some type
of data is not effective - in fact - you can turn your data into being
ever bigger in size.
So I wanted to give it a try and here is my result:
I choosed one jpg file and tested if compression is effective here:
->> img: read/binary %coins.jpg
== #{
FFD8FFE000104A46494600010201012C012C0000FFED013450686F746F73686F
7020332E30003842494D03ED000000000010012C000000010001012C0000...
->> length? img
== 221052
->> length? compress copy img
== 220809
As you can see, you will not save any significant amount of space here.
So it is clear, that compression/decompression itself will eat some cpu
time, so let's measure it:
first let's lower the size of image to some 50 kb
->> str-img: to-string copy/part img 50000
== {ÿØÿà^@^PJFIF^@^A^B^A^A,^A,^@^@ÿí^A4Photoshop
3.0^@8BIM^Cí^@^@^@^@^@^P^A,^@^@^@^A^@^A^A,^@^@^@^A^@^A8BIM^Có^@^@^@^@^@^H^@^@
^@^@^...
Now let's go to test. Each test was performed twice, to remove possible
random result times ...
Rugby compressed:
->> s: now/time loop 10 [echo mold str-img] print now/time - s
0:02:24
->> s: now/time loop 10 [echo mold str-img] print now/time - s
0:02:24
Rugby non compressed:
->> s: now/time loop 10 [echo mold str-img] print now/time - s
0:01:02
->> s: now/time loop 10 [echo mold str-img] print now/time - s
0:01:02
Some 130 % difference in performance ... So - is that correct to
compress transmitted data by default? It depends upon what you use Rugby
for. If you generate some XML/HTML/textual content, yo are probably OK.
But if you are not?
I am fully after compressing stubs transfer for e.g., as we saw
significant difference with GoRim app - 46KB vs 6KB. But I would better
let the user to decide, if he/she wants to use compression or not ....
So, please, if I am not corrent in some points, feel free to corret me
:-) E.g. look at following case:
->> s: now/time loop 10 [x: compress str-img decompress x x: compress
str-img decompress x] print now/time - s
0:00:01
compression/decompression is used two times in Rugby, so I just tested
it. Of course I don't know, how large chunks of data are transferred at
once, and so how many compression/decompression operations are applied,
but even full size of tested image compression/decompression as used in
an example, takes only 1 sec, so where does tested difference comes
from? ...
Cheers,
-pekr-
