launchpad-dev team mailing list archive

[Bryce Harrington <bryce@xxxxxxxxxxxxx>]

On Fri, Jul 23, 2010 at 08:50:03AM +0100, Graham Binns wrote:
> On 23 July 2010 08:47, Graham Binns <graham@xxxxxxxxxxxxx> wrote:
> > On 23 July 2010 08:33, Matthew Revell <matthew.revell@xxxxxxxxxxxxx> wrote:
> >> This came up in my Google alert: an Nvidia users forum post about
> >> Launchpad bug pages being very slow to scroll in Firefox:
> >>
> >> http://www.nvnews.net/vbulletin/showthread.php?s=6630abff90e878b0b6a7cd764591acd8&t=152295
> >>
> >> Just thought I'd post it here in case it was of interest.
> >
> > Javascript, j'accuse!
> 
> Ah, no, upon *actually reading the thread* (gosh), it looks like it
> appears to be a browser problem (Firefox is the culprit, though
> Chromium is also described as not working very well.
> 
> I'm not actually sure that there's a huge amount we can do about this.

"Slow scrolling in web browser" is one of the bog standard performance
regressions we see with the linux kernel and its video drivers.  In
fact, it's one of the test cases the kernel team and I have for driver
performance.  In the past I've also seen this in relation to some
graphics libraries (one of the libcairo-* components iirc).

Generally when I've worked on these in the past the root cause ended up
being some peculiarity of png images being used in the page, but it
could be any of a lot of different things.  There's some pretty basic
analysis the user could do to help narrow it down (e.g. reproduce it on
a local copy of the .html, then start snipping out html elements to
identify what specific element(s) cause it).  From there either
Launchpad could workaround by omitting those elements, or the issue can
be taken up with NVIDIA or the kernel folks for a real fix.

There's also potential for this to be a configuration issue.  Especially
with -nvidia there are ways to screw up installation (mixing up the
-nvidia and -nouveau GLX libraries, upgrading the kernel without also
rebuilding the -nvidia driver, etc.)  Also, we see a lot of "me too"ing
onto these kinds of issues by people with only vaguely similar
symptoms.  So I would really suggest having these people go through the
standard technical support channels to rule out simple user error first.

Bryce