Dear Faidon,
I would like to follow up on our discussions about pre-rendering thumbnails on the back-end, so users can see images faster when they load them in Media Viewer.
How are you coming along with this project? My understanding is that ops procured the hardware needed for that task weeks ago, but needed more time to set up a server-side image pre-rendering service.
We’re still getting a lot of user feedback that images take too long to load, particularly from users with slow connections. We’ve implemented as many solutions as we could find to speed up image load on the front-end, but are now running out of options. So the back-end pre-rendering approach is our only hope for addressing these user concerns at this time.
What do you think is a reasonable ETA for this solution from your perspective? Is there anyone on your team we should be working with to help make this happen? I know you’ve talked to Gilles about this in the past, but wanted to follow up now, since he’s on vacation this week and you will soon become less available. :)
Look forward to working together to add this last missing piece to improve the viewing experience for our users — as well as address performance issues across our sites.
Cheers,
Fabrice
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Fabrice Florin Product Manager Wikimedia Foundation
Fabrice Florin, 26/06/2014 02:15:
discussions about pre-rendering thumbnails on the back-end
Just this morning I was looking for a summary of this discussion, but I couldn't find any. Is there a wiki page proposal or bugzilla enhancement request? I wanted to cc Sam Wilson on it, he said this is also relevant for DreamHost users. Please add relevant pages to this fresh category I just created: https://www.mediawiki.org/wiki/Category:Thumbnailing
Nemo
On Thu, Jun 26, 2014 at 1:29 AM, Federico Leva (Nemo) nemowiki@gmail.com wrote:
Just this morning I was looking for a summary of this discussion, but I couldn't find any. Is there a wiki page proposal or bugzilla enhancement request? I wanted to cc Sam Wilson on it, he said this is also relevant for DreamHost users.
There is now: https://bugzilla.wikimedia.org/show_bug.cgi?id=67698
Gergo Tisza, 09/07/2014 00:55:
There is now: https://bugzilla.wikimedia.org/show_bug.cgi?id=67698
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_perform...
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
On Fri, Jul 11, 2014 at 2:24 PM, Federico Leva (Nemo) nemowiki@gmail.com wrote:
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?
By "one or the other" you mean image load time for varnish hits vs. image load time for varnish misses (on-demand generated thumbnails)? We are measuring all MediaViewer image loads (with some random sampling to keep the volume sane), and check the X-Varnish headers to tell if it was a hit or a miss. I see no potential for selection bias there.
multimedia@lists.wikimedia.org