wasm-opt performance

I am working what would expect to be a rather large c++ code based and compiling for webassembly

One thing i have noticed during the process is the performance of wasm-opt across my .wasm file. I am wondering if there is anything i can do to help profile where the bottlenecks are in wasm-opt and if we can address them.

Here is breakdown of file size, and run time of wasm-opt
baseline perf.wasm -> 419.88MB
O0 38.6 MB
O1 33.6 MB
O2 29.3 MB
O3 30.7 MB
Os 28.7 MB <- Our current build optimization level
Oz 28.3 MB

ls -l perf.wasm
for OPT in 0 1 2 3 s z
do
  time /root/emsdk/upstream/bin/wasm-opt -O$OPT --strip-dwarf --post-emscripten --low-memory-unused --zero-filled-memory --strip-debug --strip-producers \
    perf.wasm -o perfO$OPT.wasm --mvp-features --enable-threads --enable-mutable-globals --enable-bulk-memory --enable-sign-ext
  ls -l perfO$OPT.wasm
  sleep 15s
done

Here is the output

-rw-r--r-- 1 root root 440277504 Apr 27 08:52 perf.wasm

real    0m12.978s
user    0m17.046s
sys     0m1.136s
-rw-r--r-- 1 root root 40548421 Apr 27 09:21 perfO0.wasm

real    0m28.735s
user    1m47.963s
sys     0m1.555s
-rw-r--r-- 1 root root 35313836 Apr 27 09:22 perfO1.wasm

real    1m44.731s
user    7m1.825s
sys     0m1.861s
-rw-r--r-- 1 root root 30765732 Apr 27 09:24 perfO2.wasm

real    2m15.277s
user    11m46.021s
sys     0m1.842s
-rw-r--r-- 1 root root 32263192 Apr 27 09:26 perfO3.wasm

real    2m2.222s
user    9m3.411s
sys     0m1.860s
-rw-r--r-- 1 root root 30136226 Apr 27 09:29 perfOs.wasm

real    1m59.970s
user    9m23.343s
sys     0m2.571s
-rw-r--r-- 1 root root 29763508 Apr 27 09:31 perfOz.wasm

Start by reproducing the reported wasm-opt timings with the provided perf.wasm input and optimization script. Profile the wasm-opt entry point across the listed -O0 through -Oz runs to identify the bottleneck; done means the costly operation is isolated and a concrete optimization scope is agreed.