On Friday, 29 May 2015 at 07:51:31 UTC, thedeemon wrote:
On Thursday, 28 May 2015 at 21:23:11 UTC, Momo wrote:
Ah, actually it's more complicated, as it depends on inlining a
lot.
Yes. And real functions are more complex and inlining is no
reliable option.
Indeed, without -O and -inline I was
On Friday, 29 May 2015 at 07:51:31 UTC, thedeemon wrote:
Above was on Core 2 Quad,
here's for Core i3:
4 ints 5 ints
-release
by ref: 67 by ref: 66
by copy: 44 by copy: 142
by move: 45 by move: 137
-release -O
by ref: 29 by ref: 29
by copy: 41 by copy: 141
by
On Thursday, 28 May 2015 at 21:23:11 UTC, Momo wrote:
Ah, actually it's more complicated, as it depends on inlining a
lot.
Indeed, without -O and -inline I was able to get by_ref to be
slightly slower than by_copy for struct of 4 ints. But when
inlining turns on, the numbers change in
On Thursday, 28 May 2015 at 21:23:11 UTC, Momo wrote:
I'm currently investigating the difference of speed between
references and copies. And it seems that copies got a immense
slowdown if they reach a size of = 20 bytes.
This is processor-specific, on different models of CPUs you might
get
Perhaps you can give me another detailed answer.
I get a slowdown for all parts (ref, copy and move) if I use
uninitialized floats. I got these results from the following code:
by ref: 2369
by copy: 2335
by move: 2341
Code:
struct vec2f {
float x;
float y;
}
But if I assign 0 to
On 05/29/2015 06:55 AM, Momo wrote:
Perhaps you can give me another detailed answer.
I get a slowdown for all parts (ref, copy and move) if I use
uninitialized floats.
Floating point variables are initialized to .nan of their types (e.g.
float.nan). Apparently, the CPU is slow when using
16 bytes is 64 bit - the same size as a reference. So copying it
is overall a bit less work - sending a 64 bit struct is as small
as a 64 bit reference and you don't go through the pointer.
So up to them, it is a bit faster.
Add another byte and now the copy is too big to fit in a
register,
On 05/28/2015 11:27 PM, Adam D. Ruppe wrote:
16 bytes is 64 bit
It's actually 128 bits.
On Thursday, 28 May 2015 at 21:27:42 UTC, Adam D. Ruppe wrote:
16 bytes is 64 bit - the same size as a reference. So copying
it is overall a bit less work - sending a 64 bit struct is as
small as a 64 bit reference and you don't go through the
pointer.
So up to them, it is a bit faster.
