Re: Speed difference in Gnus: a step in the right direction
Hrvoje Niksic wrote:
"Stephen J. Turnbull" <stephen(a)xemacs.org> writes:
>(Reading of headers is still unconscionably slow for me, but I
>believe that's documented in the Gnus manual for large nnml groups
>because of all the disk I/O needed.)
>
>
What disk I/O? nnml reads the headers from a single .overview file.
The way I understand it, nnml is supposed to be the "fast" one.
Reading the headers is fairly slow, but its speed has never been
O(n^2).
Hrvoje, if you're willing to try some profiling in a current 21.5, it
would give me some good data and we could figure out for sure where the
O(n^2) behavior is coming from. i know 21.5 has gotten slower due to
changes to the char-byte algorithm, but still, the profiling output yet
get would be immensely helpful (if you're feeling wary about the latest
21.5, you could use beta 18, although i wouldn't be modifying that.) If
you can present me with some profiles of the latest 21.5 (or of b18),
optimized w/o error-checking, of doing the operations that document the
N^2 behavior, I'll make a new 21.5 that adds appropriate profile
sections to help narrow down further what's going wrong, and also
probably make some changes based on the info you give me so that things
speed up -- e.g. see about fixing the byte-char slowdown. if it's text
props, that will take longer, but at least we'll have confirmed the
source of the problem rather than it being some yet other slowness that
i'm not aware of.
thanks,
ben