L
Lost Bits
Hello there C++ pros..
Well, I have recently redesigned an already existing piece of code
that someone else designed - its just a search algorithm they
developed, and has to perfomr millions of loops depending on the data
input..
My problem is that my code can be upto 10 times slower than the
previous persons - and speed is very critical. (and I dont mean
setting up the arrays takes long, I'm more concernted about the speed
of the search algorithm itself..)
The only difference between my code and the other persons code is that
I am
using subscirpt math to represent 2D arrays using 1D arrays, (so every
access to an array has to do that extra math), also my code is more
object oriented, so more levels of indirection - but I try passing my
classes by reference so that it doesnt have to sepnd extra time
actually copying the data, only time to dereference the address..
ANd finally, I use the new/delete operators instead of malloc/free
I tried mashing my classes together to remove levels of indirection,
but by doing that I had to create more arrays using 'new', and my code
got even slower!!??
Then I decided to get rid of the subscritp math and i created dynamic
2D arrays instead of 1D arrays, and still no difference.
So the algorithm is the same, same number of loops etc, so this is not
the problem,
now the only difference left is that I'm using the new/delete
operators. DO you think this will affect my virtual memory or
something lets say and this is causing the search to slow down?
I've hit a roadblock!
I even profiled using gprof, and the only confuins thing is that its
telling me that 'internal_mcount' takes alot of time, i dont know what
the heck this is
this is wat it says:
called/total parents
index %time self descendents called+self name index
called/total children
<spontaneous>
[1] 60.1 198.18 0.00 internal_mcount [1]
0.00 0.00 1/3 atexit [112]
-----------------------------------------------
but yeah anyways, so do you think its the malloc/free new/delete
thing?
your hlep is very apprecieated
htanks!
lost bits =(
Well, I have recently redesigned an already existing piece of code
that someone else designed - its just a search algorithm they
developed, and has to perfomr millions of loops depending on the data
input..
My problem is that my code can be upto 10 times slower than the
previous persons - and speed is very critical. (and I dont mean
setting up the arrays takes long, I'm more concernted about the speed
of the search algorithm itself..)
The only difference between my code and the other persons code is that
I am
using subscirpt math to represent 2D arrays using 1D arrays, (so every
access to an array has to do that extra math), also my code is more
object oriented, so more levels of indirection - but I try passing my
classes by reference so that it doesnt have to sepnd extra time
actually copying the data, only time to dereference the address..
ANd finally, I use the new/delete operators instead of malloc/free
I tried mashing my classes together to remove levels of indirection,
but by doing that I had to create more arrays using 'new', and my code
got even slower!!??
Then I decided to get rid of the subscritp math and i created dynamic
2D arrays instead of 1D arrays, and still no difference.
So the algorithm is the same, same number of loops etc, so this is not
the problem,
now the only difference left is that I'm using the new/delete
operators. DO you think this will affect my virtual memory or
something lets say and this is causing the search to slow down?
I've hit a roadblock!
I even profiled using gprof, and the only confuins thing is that its
telling me that 'internal_mcount' takes alot of time, i dont know what
the heck this is
this is wat it says:
called/total parents
index %time self descendents called+self name index
called/total children
<spontaneous>
[1] 60.1 198.18 0.00 internal_mcount [1]
0.00 0.00 1/3 atexit [112]
-----------------------------------------------
but yeah anyways, so do you think its the malloc/free new/delete
thing?
your hlep is very apprecieated
htanks!
lost bits =(