WRT to transaction changes: are any of them even in stable in the first place?

Mac + Windows curves are basically all[1] blockfile, Linux is simple. I have no clue on the nature of the iOS version... You didn't seem to have included the Android version (always Simple), and that seems to have a virtually identical shape to the Windows one at 95th percentile. (And same shape, just much worse, at 50th). So I doubt it's specific to a backend.

What's weird is that there doesn't seem to be any sort of same-thing-but-6-weeks-earlier going on with the Beta curve, too. 

Timing-wise it seems close to 60.0.3112.113, but that doesn't seem to have anything that sticks out in the changelog:
https://chromium.googlesource.com/chromium/src/+log/60.0.3112.101..60.0.3112.113?pretty=fuller&n=10000


Maybe some experiment?
8/24 had PlzNavigate changes(?) in stable, would that be potentially reflected here?
Also some stuff about New Tab Page which could potentially move stuff around if very different.


To make it potentially more confusing:
I have also been concerned about HttpCache.AccessToDone.Used --- which is a very similar metric --- rising in canary on both backends, but that's quite removed code-age-wise....

https://uma.googleplex.com/p/chrome/timeline_v2/?sid=373384d23d45421becd80eb7d6f9db04
https://uma.googleplex.com/p/chrome/timeline_v2/?sid=12c5f6c40245c69d3252c42e757025be


[1] as in everyone who isn't playing with about:flags

Hmm, PlzNavigate stuff got disabled on Sept. 8th, so probably not it? 

The Http Cache Transaction changes are in M61 and Win/Mac/Linux got M61 stable release on Sep 14. So looks like this rise is not related to those changes.