[Pan-devel] Re: CVS version and download speed

[Duncan]

Tom Dexter posted
<address@hidden>, excerpted
below,  on Sun, 02 Oct 2005 10:59:37 -0500:

> 
> I mentioned this in an email to the list a few months ago, and was curious
> if anyone else has noticed this.
> 
> I have a cable modem and normally get close to full 10 Mbps downloads.
> With the 0.14.2 verions of pan I can generally get my full bandwidth when
> downloading...800 KB/sec to over 1 MB/sec.  With the current CVS (and the
> one from several months ago) it simply seems incapable of exceeding 300
> KB/sec, often staying around 100-200.
> 
> This is compiled on an x86 system running the latest Gentoo (2.6 kernel).
> Any suggestions would be appreciated.

The CVS version is a SERIOUS rewrite of the back-end.  It now uses less
memory and does some other things differently, but will take a bit more
CPU while downloading.  You don't say what sort of CPU you are running,
but take a look at CPU usage and see if it's running high.  If so, that's
your problem.

I'm not running CVS here, and AM running a dual Opteron (amd64, Gentoo
here, too =8^), so even if I was, my numbers wouldn't mean much for you.
However, taking a wild guess, if your CPU is say a 1.5GHz or slower, it's
possible that's it.

Also note that the download method has been reworked some as well.  I
don't believe it's using libgnet as the release versions do.  That may
also be an issue, depending on how many download threads to how many news
servers you are running.  Again, I'm not running CVS so I can't say how
/much/ different it is in practice, but double-check that you have it
configured for the correct amount of download threads (up to four per
server allowed in the release versions, don't know about CVS).  It's
possible you were running multiple threads before, and it's either
configured for only one or two, now, or it's configured right but the new
code may not be well optimized or may be buggy.

Finally, check your CFLAGS.  (Gentoo specific) Note that compiling from
CVS will bypass the CFLAGS you have set in make.conf, since it's not
compiling thru portage. You'll probably want to manually set a shell
variable with your preferred CFLAGS, before compiling anything outside of
portage, so you still get the ones you want.  (Also note that since you
are compiling outside portage, you won't have portage filtering anything
out of CFLAGS that's known not to work on a particular package, so
consider scaling back a bit if something breaks.)

-- 
Duncan - List replies preferred.   No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master."  Richard Stallman in
http://www.linuxdevcenter.com/pub/a/linux/2004/12/22/rms_interview.html