Update triage/2022-03-15.md

Co-authored-by: Mark Rousskov <[email protected]>

Author: rylev

triage/2022-03-15.md

@@ -1,6 +1,6 @@
 # 2022-03-15 Triage Log
 
-Largely a quiet week. The perf improvement highlight is the use of real world crates such as `syn`, `cargo`, and `serde` in the collecting of profile guided optimization (PGO) profiles. Previously only `libcore` was used. This led to some decent improvement in compilation of real world crates (upwards of 5.5%). 
+Largely a quiet week. The perf improvement highlight is the use of real world crates such as `syn`, `cargo`, and `serde` in the collecting of profile guided optimization (PGO) profiles for LLVM. Previously only `libcore` was used for LLVM, though rustc PGO had more crates involved. This led to some decent improvement in compilation of real world crates (upwards of 5.5%). 
 
 On the regression side, the regressions were all largely small but contained inside of rollups making them hard to diagnose and correct. The perf team continues to work on process improvements that make changes to the compiler land through CI quickly while minimizing perf regressions that can sneak through.