SB2.RemoteCall.Elapsed increased as follows:

5th%: 7->9%
50th%: 20->31ms
95th%: 140->210ms

It showed up on M54-dev on Aug 9, then later on M54 Beta, now recently on Stable. It appears to have landed just after M53 was branched.
https://uma.googleplex.com/timeline_v2?sid=96db1b09f8509b0ef4bf362dc5a6d83f
I can't find evidence it's affecting page load time, but I suspect it is since SB2.Delay also increased at the 95%th.

I think that bounds the CLs to the range 53.0.2785.44 -> 54.0.2823.2 though the following link seems to cover a month.
https://chromium.googlesource.com/chromium/src/+log/53.0.2785.0..54.0.2823.0?pretty=fuller&n=10000