Try caching the collect_and_partition_mono_items query

[oli-obk]

r? @ghost

an experiment to debug some performance issues encountered in #112879

[oli-obk]

@bors try @rust-timer queue

[bors]

⌛ Trying commit f40bd84 with merge 970c04e...

[bors]

☀️ Try build successful - checks-actions
Build commit: 970c04e (970c04eb5a056c029ec06235636fbb0c788fa2f8)

[rust-timer]

Finished benchmarking commit (970c04e): comparison URL.

Overall result: ❌ regressions - ACTION NEEDED

Benchmarking this pull request likely means that it is perf-sensitive, so we're automatically marking it as not fit for rolling up. While you can manually mark this PR as fit for rollup, we strongly recommend not doing so since this PR may lead to changes in compiler perf.

Next Steps: If you can justify the regressions found in this try perf run, please indicate this with @rustbot label: +perf-regression-triaged along with sufficient written justification. If you cannot justify the regressions please fix the regressions and do another perf run. If the next run shows neutral or positive results, the label will be automatically removed.

@bors rollup=never
@rustbot label: -S-waiting-on-perf +perf-regression

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	0.8%	[0.2%, 1.9%]	24
Regressions ❌ (secondary)	1.5%	[1.1%, 2.5%]	3
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.8%	[0.2%, 1.9%]	24

Max RSS (memory usage)

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	0.8%	[0.8%, 0.8%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-2.2%	[-5.5%, -0.6%]	5
Improvements ✅ (secondary)	-1.7%	[-1.7%, -1.7%]	1
All ❌✅ (primary)	-1.7%	[-5.5%, 0.8%]	6

Cycles

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	1.3%	[0.6%, 2.1%]	2
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-1.5%	[-2.1%, -1.0%]	5
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-0.7%	[-2.1%, 2.1%]	7

Binary size

This benchmark run did not return any relevant results for this metric.

Bootstrap: 669.477s -> 670.391s (0.14%)
Artifact size: 308.51 MiB -> 308.52 MiB (0.00%)

[oli-obk]

Somewhat baffled as to why removing an eval_always would lead to an increase in actual work being done. An increase in caching I understand.

@cjgillot you always have very on-point query system insights, any idea here?

[bjorn3]

If eval_always is passed I believe we skip recording query dependencies and some other things.

[oli-obk]

oh... that makes sense. I mistakenly thought that other queries also got more expensive or called more often, but looking again that does not seem to be the case.

Thanks!