What is "merged events" doing in the context of bazel

[Ryang20718]

Page link:

No response

Problem description (include actual vs expected text, if applicable):

We have a couple of bazel test actions that are taking a lot time in the case of a cold disk ssd with the bazel test output actually stored in the remote cache.

i.e we're facing the following scenario

CI runner 1 spins up
CI runner 1 runs bazel test A with a remote cache, finished and caches the test result
CI runner 1 ran test B, didn't finish and got preempted.
CI runner 1 spins down

CI Runner 2 spins up
CI runner 2 runs test A and does some building, finishes and leverages the remote cache output for the test result, but still took 40-80s when running bazel test
CI runner 2 runs test B.......

Profiling the run above we see a lot of merged events what does this entail? Is there anyway to speed this portion up?
Is this the remote cache being slow?

Where do you see this issue? (include link to specific section of the page, if applicable)

We're not sure how to interpret this bazel performance trace

Any other information you'd like to share?

We're on bazel 6.5 with --remote_download_minimal. we'd like to know if this is an issue with our remote cache being slow or if this is the bazel server being slow or something else 🤔

[tjgq]

Can you capture a profile with --noslim_profile so we can see what the merged events correspond to?