added summary.

Author: pnkfelix

triage/2024-07-02.md

@@ -1,9 +1,12 @@
 # 2024-07-02 Triage Log
 
-Over the past 30 days, serde incr-patched:println first had a series
-of wins, accumulating 0.94% instruction count performance circa PR #126965,
-but then had a series of regression culminating with a net regression
-of 0.59% in instruction count over 30 days.
+We saw a large set of primary benchmarks regress, mostly due to PR
+#120924 (`lint_reasons` and `#[expect]`) and PR #120639 (new effects
+desugaring). Separate from those, there are a couple rollup PRs
+(#127076, #127096) with some regressions that were limited to
+relatively few benchmarks; pnkfelix was unable to isolate a injecting
+PR that can be identified as a root cause (outside assistance
+welcome!).
 
 Triage done by **@pnkfelix**.
 Revision range: [c3d7fb39..cf2df68d](https://perf.rust-lang.org/?start=c3d7fb398569407350abe044e786bc7890c90397&end=cf2df68d1f5e56803c97d91e2b1a9f1c9923c533&absolute=false&stat=instructions%3Au)
@@ -36,8 +39,8 @@ Rollup of 7 pull requests [#126951](https://github.com/rust-lang/rust/pull/12695
 
 * regressions are all to serde incr-patched:println {check, debug, opt}.
 * on its own, the regression is limited to instruction counts, and seems minor enough to not warrant deeper investigation.
+* (the 30-day history tells a slightly more complex story, though)
 * marked as triaged
-* (the 30-day history tells a slightly different story, noted in the summary)
 
 Let's `#[expect]` some lints: Stabilize `lint_reasons` (RFC 2383)  [#120924](https://github.com/rust-lang/rust/pull/120924) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=d7c59370cea68cd17006ec3440a43254fd0eda7d&end=4bc39f028d14c24b04dd17dc425432c6ec354536&stat=instructions:u)
 
@@ -309,8 +312,3 @@ Avoid MIR bloat in inlining [#127113](https://github.com/rust-lang/rust/pull/127
 - [#122976 Remove len argument from RawVec::reserve_for_push](https://github.com/rust-lang/rust/pull/122976)
 - [#122900 Rollup of 8 pull requests](https://github.com/rust-lang/rust/pull/122900)
 - [#122671 Codegen const panic messages as function calls](https://github.com/rust-lang/rust/pull/122671)
-
-#### Nags requiring follow up
-
-TODO: Nags
-