commit 2ec9017bb1de7d5ba552c1f016326088864b9cf9
author Ben Vanik <ben.vanik@gmail.com> Wed Oct 30 16:18:44 2024 -0700
committer GitHub <noreply@github.com> Wed Oct 30 16:18:44 2024 -0700
tree 765e826efb85dcbee22de33b42dcef28970d0ef0
parent a744285e3c1a291bd7579cb3a1e699c1a114dba6

Improving VM conversion performance. (#18957)

The major change here is using a precomputed import table in VM
conversion patterns. This removes the symbol lookup that was happening
on each call. In models with 100k calls to imports this speeds things up
a lot.

Also squashed a few more perf issues involving symbol lookups while
profiling and made some passes that could nest on function-like ops do
so.

These changes drop VM translation of the 405b model from 3.5mins to
~1.5min. Disabling verification (`-verify-each=0` to iree-opt or
`-verify=false` to iree-compile) takes it to 1min.

Remaining work is mostly around parallelizing some passes that are not
trivially parallelizable (FoldGlobals, DropUnusedCalls, etc) and
parallelizing some analysis (Explorer global init, call graph walking)
that tends to get real expensive when there are 250k calls and 500k ops.
Any place that does a symbol use walk is going to suffer. Many of these
fixes are in our code but there's several upstream components that fall
over with this amount of IR (CallGraph, DataFlowSolver, the verifier,
etc).