New issue
Advanced search Search tips
Note: Color blocks (like or ) mean that a user may not be available. Tooltip shows the reason.

Issue 774509 link

Starred by 1 user

Issue metadata

Status: Verified
Owner:
Closed: Jun 2018
Cc:
Components:
EstimatedDays: ----
NextAction: ----
OS: ----
Pri: 2
Type: Bug

Blocking:
issue 682680



Sign in to add a comment

Extensions.FunctionCalls Is Overflowing

Project Member Reported by bcwh...@chromium.org, Oct 13 2017

Issue description

The Extensions.FunctionCalls sparse histogram is being incremented so frequently that it sometimes overflows the 31-bit sample count and rolls negative.  Desktop does uploads about every 30 minutes (and resets the counters) so whatever extension these are, it's happening on the order of 1M times per second on some occasions.

https://uma.googleplex.com/p/chrome/histograms/?endDate=20171011&dayCount=1&histograms=Extensions.FunctionCalls%2CUMA.NegativeSamples.Histogram&fixupData=true&showMax=true&filters=isofficial%2Ceq%2CTrue&implicitFilters=isofficial

Given that this is a "slow" sparse histogram, which involves acquiring a lock, there may be significant overhead here, hence the P2.
 
Blocking: 682680
Cc: -devlin@chromium.org karandeepb@chromium.org bcwh...@chromium.org catmulli...@chromium.org lazyboy@chromium.org
Components: Platform>Extensions
Owner: rdevlin....@chromium.org
Wow.  Talked with bcwhite about this a bit.  Notes:
- This means that a specific value for the histogram is being recorded > 2^31 times in a sampling period.  In this case, that means a specific function.
- Sampling periods are about 30 minutes.  They can be delayed, but not too long.  And, even in an extremely broken case (uploading once a month!), this is still executing 828 calls per second!

This is definitely relevant to our discussion about "sane limits" from the other day.

bcwhite@ is landing a fix that will help us tell how prolific this is, but whatever the answer, it's something we should address.
Cc: -catmulli...@chromium.org
Status: Fixed (was: Assigned)
I'm not seeing this any longer.
Status: Verified (was: Fixed)

Sign in to add a comment