Gilles (Gilles Dubuc)
Senior Performance Engineer, WMF

Projects (18)

Today

  • Clear sailing ahead.

Tomorrow

  • Clear sailing ahead.

Wednesday

  • Clear sailing ahead.

User Details

User Since
Oct 7 2014, 8:24 AM (137 w, 6 d)
Availability
Available
IRC Nick
gilles
LDAP User
Gilles
MediaWiki User
Unknown

Recent Activity

Sat, May 27

Gilles added a comment to T116515: Enable embedding of media from Wikimedia Commons.

I can try writing that this summer, right now I'm swamped until the end of the quarter.

Sat, May 27, 6:47 AM · Phabricator

Fri, May 26

Gilles created T166414: Explore NavigationTiming by faceted properties.
Fri, May 26, 9:06 PM · Analytics, Performance-Team
Gilles moved T156537: 504 Gateway Time-out on https://de.wikipedia.org/w/index.php?title=Wikipedia:L%C3%B6schkandidaten&action=info from Inbox to Radar on the Performance-Team board.
Fri, May 26, 4:32 PM · Performance-Team, MediaWiki-Database, Wikimedia-General-or-Unknown
Gilles moved T164299: Preload base modules request from Inbox to Next-up on the Performance-Team board.
Fri, May 26, 4:30 PM · Performance-Team, MediaWiki-ResourceLoader
Gilles triaged T127628: Create a bot that automatically optimizes PNGs as Low priority.
Fri, May 26, 4:26 PM · Performance-Team, Gerrit, Release-Engineering-Team (Watching / External), Performance
Gilles moved T127628: Create a bot that automatically optimizes PNGs from Inbox to Backlog on the Performance-Team board.
Fri, May 26, 4:26 PM · Performance-Team, Gerrit, Release-Engineering-Team (Watching / External), Performance
Gilles moved T165714: BagOStuff::trackDuplicateKeys causes a "MWCallableUpdate::doUpdate: transaction round ..." during JobRunner::executeJob from Inbox to Next-up on the Performance-Team board.
Fri, May 26, 4:25 PM · MediaWiki-JobQueue, Performance-Team, MediaWiki-Database
Gilles closed T165776: Collect connection type in Navigation Timing as Invalid.

Already collected by a cookie that makes it into EventLogging, it's just not exposed in Grafana.

Fri, May 26, 4:22 PM · Performance-Team
Gilles moved T166129: HTTP/1 vs HTTP/2 from Inbox to Doing on the Performance-Team board.
Fri, May 26, 4:14 PM · Performance-Team
Gilles moved T124418: Investigate massive increase in htmlCacheUpdate jobs in Dec/Jan from Inbox to Radar on the Performance-Team board.
Fri, May 26, 4:08 PM · Performance-Team, Wikidata, MediaWiki-Cache, MediaWiki-JobQueue, Traffic, Operations
Gilles moved T162719: Appended mw.loader.state() creates invalid response on load.php?only=scripts if content ends without semi-colon from Inbox to Next-up on the Performance-Team board.
Fri, May 26, 4:04 PM · Performance-Team, MediaWiki-ResourceLoader
Gilles moved T166374: Custom domain/URL for phame performance blog from Inbox to Radar on the Performance-Team board.
Fri, May 26, 3:57 PM · Release-Engineering-Team, Phabricator, Performance-Team
Gilles added a comment to T147569: Evaluate/Deploy TCP BBR when available (kernel 4.9+).

@BBlack one way to verify that the performance improvement we're seeing is "real" would be to turn BBR off for a bit. That being said, it will still be a simulated slow connection and that alone doesn't tell us the effect in the real world, if any.

Fri, May 26, 12:48 PM · Patch-For-Review, Performance-Team, Operations, Traffic
Gilles added a comment to T166373: Investigate apparent performance improvement around 2017-05-24.

Could be, yes. The BBR improvement could be verified by turning it off. Let's discuss that on the BBR task.

Fri, May 26, 12:43 PM · Reading-Web-Backlog, MobileFrontend, Performance-Team
Gilles closed T166373: Investigate apparent performance improvement around 2017-05-24 as Resolved.

Found it: T150325: Move first paragraph before infobox on stable

Fri, May 26, 12:38 PM · Reading-Web-Backlog, MobileFrontend, Performance-Team
Gilles added a comment to T166373: Investigate apparent performance improvement around 2017-05-24.

Trying it out in my own browser, it does look like a deliberate change, as the first section is nicer to read at the top than the infobox on a width-constrained browser.

Fri, May 26, 12:33 PM · Reading-Web-Backlog, MobileFrontend, Performance-Team
Gilles added a comment to T166373: Investigate apparent performance improvement around 2017-05-24.

Same for Sweden. Before:

Fri, May 26, 12:31 PM · Reading-Web-Backlog, MobileFrontend, Performance-Team
Gilles added a comment to T166373: Investigate apparent performance improvement around 2017-05-24.

Something that might be noteworthy, looking at the Facebook article.

Fri, May 26, 12:27 PM · Reading-Web-Backlog, MobileFrontend, Performance-Team
Gilles added a comment to T147569: Evaluate/Deploy TCP BBR when available (kernel 4.9+).

There is an apparent performance improvement that coincides in timing, but on a simulated slow internet connection:

Fri, May 26, 10:14 AM · Patch-For-Review, Performance-Team, Operations, Traffic
Gilles renamed T166374: Custom domain/URL for phame performance blog from Custom domain/URL for performance blog to Custom domain/URL for phame performance blog.
Fri, May 26, 9:57 AM · Release-Engineering-Team, Phabricator, Performance-Team
Gilles added a comment to T166373: Investigate apparent performance improvement around 2017-05-24.

No visible impact in RUM (looking at firstPaint in NavigationTiming). But if it only affects large articles, it's not that surprising, as we saw with the logo preload.

Fri, May 26, 9:57 AM · Reading-Web-Backlog, MobileFrontend, Performance-Team
Gilles triaged T166373: Investigate apparent performance improvement around 2017-05-24 as Normal priority.
Fri, May 26, 9:54 AM · Reading-Web-Backlog, MobileFrontend, Performance-Team
Gilles created T166374: Custom domain/URL for phame performance blog.
Fri, May 26, 9:53 AM · Release-Engineering-Team, Phabricator, Performance-Team
Gilles created T166373: Investigate apparent performance improvement around 2017-05-24.
Fri, May 26, 9:38 AM · Reading-Web-Backlog, MobileFrontend, Performance-Team
Gilles moved T166112: Enable storage and display of OGV and WEBM videos on Phabricator from Inbox to Radar on the Performance-Team board.
Fri, May 26, 9:32 AM · Project-Admins, Phabricator, Release-Engineering-Team (Kanban), Performance-Team
Gilles added a comment to T116515: Enable embedding of media from Wikimedia Commons.

Looking at the code, it seems like an iframe for Youtube, and Commons does have a URL to be put in an iframe, so that's perfect. I think we need the actual Commons video player because:

Fri, May 26, 9:29 AM · Phabricator
Gilles added a comment to T166112: Enable storage and display of OGV and WEBM videos on Phabricator.

Fair enough, re: our information leaking to google. I think that's a clear deal breaker.

Fri, May 26, 9:27 AM · Project-Admins, Phabricator, Release-Engineering-Team (Kanban), Performance-Team
Gilles closed T166110: Create Performance phame blog as Resolved.

It does, thanks.

Fri, May 26, 9:18 AM · Phabricator, Release-Engineering-Team (Kanban), User-greg, Performance-Team
Gilles renamed The speed of thought blog from Performance to The speed of thought.
Fri, May 26, 9:14 AM · Performance-Team
Gilles created The speed of thought.
Fri, May 26, 9:13 AM · Performance-Team
Gilles moved T166110: Create Performance phame blog from Inbox to Radar on the Performance-Team board.
Fri, May 26, 9:12 AM · Phabricator, Release-Engineering-Team (Kanban), User-greg, Performance-Team

Wed, May 24

Gilles added a comment to T166110: Create Performance phame blog.

It still states:

Wed, May 24, 7:11 PM · Phabricator, Release-Engineering-Team (Kanban), User-greg, Performance-Team
Gilles added a comment to T166112: Enable storage and display of OGV and WEBM videos on Phabricator.

We do host all our recorded meetings on youtube in addition to commons, there would some convenience in being able to link to that... We should ask people who clean up phabricator spam/moderate it if they'd be ok with the risk of opening that up. @Aklapper what do you think?

Wed, May 24, 7:10 PM · Project-Admins, Phabricator, Release-Engineering-Team (Kanban), Performance-Team
Gilles added a comment to T150741: Thumbor should reject thumbnail requests that are the same size as the original or bigger.

refreshFileHeaders is still dreadfully slow even with batching and not needing to look at metadata, unfortunately. I think I'll focus on implementing the fallback in Thumbor first...

Wed, May 24, 7:06 PM · MW-1.30-release-notes (WMF-deploy-2017-05-23_(1.30.0-wmf.2)), Patch-For-Review, Operations, Performance-Team, Thumbor
Gilles added a comment to T166112: Enable storage and display of OGV and WEBM videos on Phabricator.

Another option is allowing youtube embedding...

Wed, May 24, 4:58 PM · Project-Admins, Phabricator, Release-Engineering-Team (Kanban), Performance-Team
Gilles added a comment to T166112: Enable storage and display of OGV and WEBM videos on Phabricator.

Well, a higher limit (or unlimited in that case) could require special rights. But I imagine that requires upstream work, right?

Wed, May 24, 4:48 PM · Project-Admins, Phabricator, Release-Engineering-Team (Kanban), Performance-Team
Gilles added a comment to T166112: Enable storage and display of OGV and WEBM videos on Phabricator.

Possibly a regression, then, both .ogv and .webm files I try show an error when the upload reaches 100%:

Wed, May 24, 2:30 PM · Project-Admins, Phabricator, Release-Engineering-Team (Kanban), Performance-Team
Gilles committed rTHMBREXTbd8ec9608c46: Version bump (authored by Gilles).
Version bump
Wed, May 24, 2:19 PM
Gilles committed rTHMBREXTbbaa7a59670e: handler: safer mc key encoding (authored by fgiunchedi).
handler: safer mc key encoding
Wed, May 24, 2:17 PM
Gilles closed D659: handler: safer mc key encoding by committing rTHMBREXTbbaa7a59670e: handler: safer mc key encoding (authored by fgiunchedi).
Wed, May 24, 2:17 PM
Gilles accepted D659: handler: safer mc key encoding.
Wed, May 24, 2:14 PM
Gilles committed rTHMBREXTe328779a4b6b: handler: hash mc keys (authored by fgiunchedi).
handler: hash mc keys
Wed, May 24, 10:44 AM
Gilles closed D658: handler: hash mc keys by committing rTHMBREXTe328779a4b6b: handler: hash mc keys (authored by fgiunchedi).
Wed, May 24, 10:44 AM
Gilles accepted D658: handler: hash mc keys.
Wed, May 24, 10:41 AM
Gilles requested changes to D658: handler: hash mc keys.
Wed, May 24, 9:17 AM

Tue, May 23

Gilles triaged T166144: mediawiki-core-phpcs-trusty broken, can't find hhvm in path as Unbreak Now! priority.
Tue, May 23, 3:46 PM · Release-Engineering-Team (Kanban), Jenkins
Gilles created T166144: mediawiki-core-phpcs-trusty broken, can't find hhvm in path.
Tue, May 23, 3:45 PM · Release-Engineering-Team (Kanban), Jenkins
Gilles added a project to T166112: Enable storage and display of OGV and WEBM videos on Phabricator: Phabricator.
Tue, May 23, 8:55 AM · Project-Admins, Phabricator, Release-Engineering-Team (Kanban), Performance-Team
Gilles reassigned T166110: Create Performance phame blog from greg to mmodell.
Tue, May 23, 8:54 AM · Phabricator, Release-Engineering-Team (Kanban), User-greg, Performance-Team
Gilles created T166112: Enable storage and display of OGV and WEBM videos on Phabricator.
Tue, May 23, 8:54 AM · Project-Admins, Phabricator, Release-Engineering-Team (Kanban), Performance-Team
Gilles triaged T166110: Create Performance phame blog as Normal priority.
Tue, May 23, 8:46 AM · Phabricator, Release-Engineering-Team (Kanban), User-greg, Performance-Team
Gilles created T166110: Create Performance phame blog.
Tue, May 23, 8:45 AM · Phabricator, Release-Engineering-Team (Kanban), User-greg, Performance-Team

Sun, May 21

Gilles added a comment to T150741: Thumbor should reject thumbnail requests that are the same size as the original or bigger.

Assuming the above change works and we only need to run refreshFileHeaders for the migration, let's estimate how long it would take for commons if we simply ran the migration script on Terbium.

Sun, May 21, 11:13 AM · MW-1.30-release-notes (WMF-deploy-2017-05-23_(1.30.0-wmf.2)), Patch-For-Review, Operations, Performance-Team, Thumbor

Sat, May 20

Gilles added a comment to T150741: Thumbor should reject thumbnail requests that are the same size as the original or bigger.

I've just realized that the existing migration scripts probably don't care about oldimage... which means that those wouldn't get the X-Content-Dimensions header. The cost of the migration thus gets even worse, since thumbnails can be generated for those old revisions.

Sat, May 20, 1:21 PM · MW-1.30-release-notes (WMF-deploy-2017-05-23_(1.30.0-wmf.2)), Patch-For-Review, Operations, Performance-Team, Thumbor
Gilles added a comment to T150741: Thumbor should reject thumbnail requests that are the same size as the original or bigger.

Since the current migration scripts are very slow on Terbium when applied to all file types, we probably have to start looking at alternatives:

Sat, May 20, 12:52 PM · MW-1.30-release-notes (WMF-deploy-2017-05-23_(1.30.0-wmf.2)), Patch-For-Review, Operations, Performance-Team, Thumbor

Fri, May 19

Gilles updated subscribers of T162796: Delete non-used and/or non-requested thumbnail sizes periodically.
Fri, May 19, 4:22 PM · Patch-For-Review, User-fgiunchedi, Operations
Gilles updated subscribers of T162796: Delete non-used and/or non-requested thumbnail sizes periodically.
Fri, May 19, 3:55 PM · Patch-For-Review, User-fgiunchedi, Operations
Gilles renamed T165776: Collect connection type in Navigation Timing from Collect connection type in Navigation Timing to Collect connection type in Navigation Timing.
Fri, May 19, 2:53 PM · Performance-Team
Gilles created T165776: Collect connection type in Navigation Timing.
Fri, May 19, 2:53 PM · Performance-Team

Wed, May 17

Gilles moved T162857: Some Core availability Catchpoint tests might be more expensive than they need to be from Inbox to Radar on the Performance-Team board.
Wed, May 17, 6:52 PM · Performance-Team, Operations
Gilles moved T164422: Check if we can reduce URLs tested on WebPageTest to make room for other wikis from Inbox to Next-up on the Performance-Team board.
Wed, May 17, 6:47 PM · Performance-Team, WebPageTest
Gilles moved T164714: Calculate parsing speed for JavaScript on mobile from Inbox to Backlog on the Performance-Team board.
Wed, May 17, 6:45 PM · Mobile, Performance-Team
Gilles moved T164986: TTFB decrease in Chrome for second view tests from Inbox to Backlog on the Performance-Team board.
Wed, May 17, 6:44 PM · Performance-Team, WebPageTest
Gilles moved T161588: Rework https://performance.wikimedia.org from Inbox to Doing on the Performance-Team board.
Wed, May 17, 6:42 PM · Performance-Team
Gilles assigned T161588: Rework https://performance.wikimedia.org to Peter.
Wed, May 17, 6:42 PM · Performance-Team
Gilles moved T52919: Error for invalid on-wiki JavaScript can show wrong filename from Inbox to Doing on the Performance-Team board.
Wed, May 17, 6:40 PM · MW-1.30-release-notes, Performance-Team, MediaWiki-ResourceLoader
Gilles moved T165272: Review research on performance perception from Inbox to Backlog on the Performance-Team board.
Wed, May 17, 6:39 PM · Performance-Team
Gilles added a comment to T150741: Thumbor should reject thumbnail requests that are the same size as the original or bigger.

I've checked and PdfHandler already handles rotation like a champ, all the way to X-Content-Dimensions. I think the change I've made in core for JPGs is all we need to do, as the remaining formats I haven't mentioned here don't have metadata rotation features.

Wed, May 17, 1:18 PM · MW-1.30-release-notes (WMF-deploy-2017-05-23_(1.30.0-wmf.2)), Patch-For-Review, Operations, Performance-Team, Thumbor
Gilles added a comment to T150741: Thumbor should reject thumbnail requests that are the same size as the original or bigger.

TIFF support for orientation on Linux seems to be mostly broken, including on Mediawiki. Any orientation that should swap dimensions (eg. 90 CW) is interpreted as a different orientation value that doesn't swap dimensions. In this sea of brokenness, this means that for X-Content-Dimensions we should ignore metadata orientation for TIFFs (single or multipage). I.e. we don't need to anything more than what we're doing currently.

Wed, May 17, 1:05 PM · MW-1.30-release-notes (WMF-deploy-2017-05-23_(1.30.0-wmf.2)), Patch-For-Review, Operations, Performance-Team, Thumbor

Tue, May 16

Gilles added a comment to T150741: Thumbor should reject thumbnail requests that are the same size as the original or bigger.

I didn't write similar integration tests for DjVu, because those depend on command line tools that aren't present by default. However I manually crafted a djvu document with a rotated page and the rotation is applied by djvutoxml, which means that Mediawiki doesn't need to do anything special.

Tue, May 16, 1:07 PM · MW-1.30-release-notes (WMF-deploy-2017-05-23_(1.30.0-wmf.2)), Patch-For-Review, Operations, Performance-Team, Thumbor
Gilles added a comment to T150741: Thumbor should reject thumbnail requests that are the same size as the original or bigger.

I've just realized that X-Content-Dimensions doesn't apply EXIF rotation, which is necessary as the Swift headers alone won't tell if the current document/page is soft-rotated...

Tue, May 16, 7:23 AM · MW-1.30-release-notes (WMF-deploy-2017-05-23_(1.30.0-wmf.2)), Patch-For-Review, Operations, Performance-Team, Thumbor

Mon, May 15

Gilles updated the task description for T150741: Thumbor should reject thumbnail requests that are the same size as the original or bigger.
Mon, May 15, 9:23 PM · MW-1.30-release-notes (WMF-deploy-2017-05-23_(1.30.0-wmf.2)), Patch-For-Review, Operations, Performance-Team, Thumbor
Gilles created T165324: Can't upload large files with X-Wikimedia-Debug turned on.
Mon, May 15, 1:51 PM · Traffic, Operations
Liuxinyu970226 awarded T132058: 3d extension supporting STL (3d printing files) a Party Time token.
Mon, May 15, 11:02 AM · User-notice, MW-1.28-release-notes, 3d, Wikimedia-Hackathon-2016, Reading-Community-Engagement, MediaWiki-File-management, Commons, Editing-Department, Multimedia
Gilles renamed T165272: Review research on performance perception from Review research on perceived performance to Review research on performance perception.
Mon, May 15, 7:33 AM · Performance-Team
Gilles created T165272: Review research on performance perception.
Mon, May 15, 7:33 AM · Performance-Team

Thu, May 11

Gilles raised the priority of T104902: Refactor Navigation Timing gathering to produce reliable stackable measures from Low to Normal.
Thu, May 11, 8:45 AM · Performance-Team
Gilles moved T104902: Refactor Navigation Timing gathering to produce reliable stackable measures from Backlog to Next-up on the Performance-Team board.
Thu, May 11, 8:45 AM · Performance-Team
Gilles merged T164749: Review Navigation Timing metrics into T104902: Refactor Navigation Timing gathering to produce reliable stackable measures.
Thu, May 11, 8:44 AM · Performance-Team
Gilles merged task T164749: Review Navigation Timing metrics into T104902: Refactor Navigation Timing gathering to produce reliable stackable measures.
Thu, May 11, 8:44 AM · Performance-Team

Wed, May 10

Gilles closed T70861: Performance review #2 of Hovercards (Popups extension) as Resolved.

FYI we usually link to the RAIL guidelines because they're easy to understand, but they're based on research that's been around for some time about what feels instantaneous, etc. It's less digestible to link to research papers, but I'll do some homework and dig up the actual research on the subject. I personally judge RAIL as informative only, not rules to follow. In most things our team deals with, for example time-to-content on pageload, lower is always better, so the quest to improve never stops and things like RAIL are irrelevant. It's only a useful thermometer when things are so slow they don't feel instantaneous anymore. But again that's more a talking point than a goal or a rule. The definition of what's instantaneous does vary between sources, and it evolves with time. People are more impatient with their devices now than they were a decade ago. Always healthy to review research on the subject, though, so I'll do it since we haven't looked at that for some time.

Wed, May 10, 9:12 PM · Page-Previews, Performance, Traffic, Operations, Reading-Web-Backlog, Performance-Team, Wikimedia-Extension-setup
Gilles closed T70861: Performance review #2 of Hovercards (Popups extension), a subtask of T70860: [GOAL] Graduate Hovercards feature (Popups extension) out of Beta Feature, as Resolved.
Wed, May 10, 9:12 PM · Reading Epics (Page Previews), Goal, Community-Liaisons, Reading-Web-Backlog, Reading-Web-Sprint-70-Lady-and-the-Trumps, Reading-Web-Planning, Category, Reading-Community-Engagement, Epic, Reading-Admin, User-notice, Notice, Page-Previews, Beta-Feature, Wikimedia-Extension-setup
Gilles added a comment to T150741: Thumbor should reject thumbnail requests that are the same size as the original or bigger.

Deployed on testwiki, works for most formats, except:

Wed, May 10, 8:44 PM · MW-1.30-release-notes (WMF-deploy-2017-05-23_(1.30.0-wmf.2)), Patch-For-Review, Operations, Performance-Team, Thumbor
Gilles added a comment to T164749: Review Navigation Timing metrics.

We could have RL report how much it found in local storage and treat it the same as cache hits in resource timing. But we won't get the gzipped size in that case. I'm not sure what you want to count, though, request count or actual size.

Wed, May 10, 5:04 PM · Performance-Team
Gilles added a comment to T162796: Delete non-used and/or non-requested thumbnail sizes periodically.

400m misses means 154 requests per second. It would at least triple the load on Thumbor. Might be possible if/once we've repurposed all existing image scalers to Thumbor.

Wed, May 10, 5:03 PM · Patch-For-Review, User-fgiunchedi, Operations
Gilles removed a project from T150741: Thumbor should reject thumbnail requests that are the same size as the original or bigger: Patch-For-Review.
Wed, May 10, 1:34 PM · MW-1.30-release-notes (WMF-deploy-2017-05-23_(1.30.0-wmf.2)), Patch-For-Review, Operations, Performance-Team, Thumbor
Gilles added a comment to T150741: Thumbor should reject thumbnail requests that are the same size as the original or bigger.

Got confirmation that varnish entries for originals normally expire in 24 hours, but it doesn't really matter anyway since Thumbor consumes directly from Swift. Still, it will be convenient for debugging to just check the headers of original links from random files on migrated wikis a day after their migration.

Wed, May 10, 1:33 PM · MW-1.30-release-notes (WMF-deploy-2017-05-23_(1.30.0-wmf.2)), Patch-For-Review, Operations, Performance-Team, Thumbor
Gilles added a comment to T150741: Thumbor should reject thumbnail requests that are the same size as the original or bigger.

In production, the migration steps also require purging, otherwise the original can be served by Varnish and doesn't get cleared with those 2 jobs. Unfortunately using the general purge means that thumbnails get purged as well, which is undesirable. Purging all thumbnails for Commons would be problematic in terms of purge load. We can afford to wait for the cached originals to expire organically, I think, I just have to confirm how long that is in the worst case.

Wed, May 10, 11:52 AM · MW-1.30-release-notes (WMF-deploy-2017-05-23_(1.30.0-wmf.2)), Patch-For-Review, Operations, Performance-Team, Thumbor

Tue, May 9

Gilles added a comment to T162796: Delete non-used and/or non-requested thumbnail sizes periodically.

The top 100 most requested sizes represent 91.21% of all requests. The remaining long tail (any size not in that 100 whitelist) represents 68% of the storage size.

Tue, May 9, 4:01 PM · Patch-For-Review, User-fgiunchedi, Operations
Gilles added a comment to T164749: Review Navigation Timing metrics.

You mean when the page itself is a cache hit? Not worrying about the resources on the page? I'm not sure that even that is possible without some usual guess work about times that represent a cache hit vs a network call:

Tue, May 9, 2:08 PM · Performance-Team
Gilles added a comment to T100999: Make the logo's loading priority higher.

Right :) But I meant as RUM. The Obama article is quite an extreme and it would have been nice to know how much it improved time-to-logo for users in practice.

Tue, May 9, 11:22 AM · MW-1.30-release-notes, Patch-For-Review, Performance-Team-notice, MW-1.29-release-notes, MediaWiki-Interface, Performance-Team
Gilles added a comment to T164749: Review Navigation Timing metrics.

Some more food for thought.

Tue, May 9, 11:18 AM · Performance-Team
Gilles closed T100999: Make the logo's loading priority higher as Resolved.

Anyway, to close the discussion on this particular task, I think now enough time has passed since yesterday's SWAT to declare that the logo preloading has absolutely nothing to do with the fetchStart/firstPaint change. I don't think I'm going to bother backporting the second part with the patch that reactivates it, it'll just go out with the train this week.

Tue, May 9, 11:08 AM · MW-1.30-release-notes, Patch-For-Review, Performance-Team-notice, MW-1.29-release-notes, MediaWiki-Interface, Performance-Team
Gilles closed T100999: Make the logo's loading priority higher, a subtask of T127328: Optimise critical rendering path, as Resolved.
Tue, May 9, 11:08 AM · Goal, Performance-Team
Gilles added a comment to T100999: Make the logo's loading priority higher.

Yeah I think that's just the global traffic really dipping, which has made things super confusing. This was really the perfect storm of: us deploying a huge amount of changes after a week of deployment was skipped, a new Chrome version ramping up, traffic in Turkey getting blocked and what looks like a global traffic dip that Turkey alone can't explain.

Tue, May 9, 10:51 AM · MW-1.30-release-notes, Patch-For-Review, Performance-Team-notice, MW-1.29-release-notes, MediaWiki-Interface, Performance-Team
Gilles renamed T164749: Review Navigation Timing metrics from Review firstPaint calculation for Chrome to Review Navigation Timing metrics.
Tue, May 9, 10:44 AM · Performance-Team
Gilles added a comment to T164749: Review Navigation Timing metrics.

Reading the Navigation TIming v2 spec, I think the argument to use fetchStart as the origin is confirmed by the breakdown of what happens in case of a redirect. When a redirect happens, after recording the redirect duration, it goes back to updating fetchStart for the new page it's been redirected to and start again from there ("step 9").

Tue, May 9, 10:42 AM · Performance-Team

Mon, May 8

Gilles added a comment to T164749: Review Navigation Timing metrics.

I've been staring at Pivot for a while and I've noticed something interesting. The report rate for fetchStart seems to follow the pageview trend for Chrome. And right now we're experiencing a dip in traffic similar to the christmas period, and that pattern is found in both datasets. What's most striking is the huge spike we had over last summer on Chrome specifically, which is found in both:

Mon, May 8, 10:31 PM · Performance-Team
Gilles added a comment to T100999: Make the logo's loading priority higher.

So far, with the logo preload turned off for a couple of hours, no change in the metrics. We'll see tomorrow, but I think this confirms that the logo preload had nothing to do with the fetchStart/firstPaint change.

Mon, May 8, 8:48 PM · MW-1.30-release-notes, Patch-For-Review, Performance-Team-notice, MW-1.29-release-notes, MediaWiki-Interface, Performance-Team
Gilles added a comment to T162796: Delete non-used and/or non-requested thumbnail sizes periodically.

Indeed, sounds like an easy win

Mon, May 8, 5:20 PM · Patch-For-Review, User-fgiunchedi, Operations