Gergo Tisza, 09/07/2014 00:55:
Thank you! Following up on the "Swift capacity" thread, a doubt
developed in the last few days in my brain:
Gergo Tisza, 06/07/2014 23:08:
Media Viewer could benefit greatly from this performance-wise.
As seen on this graph, the launch to all wikis affected the
average considerably, since users started hitting a lot of
images that didn't have Media Viewer-sized thumbnails yet:
http://multimedia-metrics.wmflabs.org/dashboards/mmv#overall_network_perfor…
This looks pretty bad. Thanks for calling it out.
I don't think it's especially bad; there is a spike after the rollout
(it can be seen more clearly if you scroll down to the imagemiss stats)
which lasts about five says, other than that it's just probably the
effect of rolling out to new userbases which have on average much worse
network conditions then the Europe/USA based ones.
If you look at wikis to which we have rolled out earlier, e.g.
http://multimedia-metrics.wmflabs.org/dashboards/mmv_enwiki#overall_network…
there is no change at all.
Which is not to say the lack of pregenerated thumbnails is not a serious
problem (I just don't think it got any worse recently). Comparing the
global imagehit and imagemiss stats, the lack of pregeneration affects
about 20% of the requests, and costs about 730ms (an extra 85% loading
time) for the median user.
This does make me wonder, what do those graphs *actually* measure? Are
they really measuring a comparable/representative set of image requests
from which we can infer that one or the other method is intrinsically
faster than the other, or are they measuring different things e.g. for
some selection bias?
Nemo