On Sun, Jul 6, 2014 at 3:34 AM, Ori Livneh <ori@wikimedia.org> wrote:

On Fri, Jul 4, 2014 at 1:03 AM, Gilles Dubuc <gilles@wikimedia.org> wrote:

Hi ops,

Has the swift capacity been increased yet thanks to the new hardware? If so, could we resume the discussion of "pre"generating specific thumbnail sizes at upload time?

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_performance-graphs-tab

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_performance-graphs-tab

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.