https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114531
Bug ID: 114531
Summary: Feature proposal for an
`-finline-functions-aggressive` compiler option
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: driver
Assignee: unassigned at gcc dot gnu.org
Reporter: rvmallad at amazon dot com
CC: rsandifo at gcc dot gnu.org
Target Milestone: ---
Created attachment 57837
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=57837&action=edit
patch to implement -finline-functions-aggressive option in GCC
This is a proposal for a user-visible GCC compiler option for aggressive
inlining that is currently only available at -O3 as internal inline parameters
(--param=early-inlining-insns=14 --param=inline-heuristics-hint-percent=600
--param=inline-min-speedup=15 --param=max-inline-insns-auto=30
--param=max-inline-insns-single=200).
I got some perf data for Envoy (https://github.com/envoyproxy/envoy) and SPEC
CPU2017 intrate benchmarks on C7g.2xlarge w Ubuntu22 + gcc-11.4.0. We see perf
gains (2% - 5%) using these aggressive inline parameters (at -O2). Attached is
a patch for this change.
We do not want to add these inline limits at ‘-O2’ itself, as we see from one
of the SPEC CPU tests that got slower. Also, more inline tuning at -O2 would
make some of the symbols not to be available for probe/ debug (that are
available when not using these aggressive inline params).
-----------------------------------------------------------------------
Envoy load_balancer_benchmark – using only 1 CPU – Iterations, higher better
$ bazel run -c opt //test/common/upstream:load_balancer_benchmark
bazel-envoy/external/local_config_cc/BUILD can be changed for adding inline
parameters/ options.
------------------------------------------------------------------------
Benchmark Iterations Baseline O2 + Inline Params Gain
------------------------------------------------------------------------
benchmarkRoundRobinLoad 1518 1596 1.05x
BalancerBuild/500/50/50
benchmarkLeastRequestLoad 1465 1514 1.03x
BalancerChooseHost/100/3/1000
benchmarkRingHashLoadBalancer 33 34 1.03x
ChooseHost/100/65536/100000
benchmarkMaglevLoadBalancer 69 72 1.04x
Weighted/500/95/75/25/10000
------------------------------------------------------------------------
copies=8 "-O2" "-Ofast" Gain "-O2 + Gain w
w Ofast inlining" inlining
500.perlbench_r 36.5 34.3 94.0% 34.4 94.2%
502.gcc_r 45.4 47.6 104.8% 47.5 104.6%
505.mcf_r 44.6 48.2 108.1% 44.3 99.3%
520.omnetpp_r 22.1 24.9 112.7% 21.9 99.1%
523.xalancbmk_r 43.8 46.3 105.7% 45.4 103.7%
525.x264_r 44.3 89 200.9% 43.8 98.9%
531.deepsjeng_r 36 37.3 103.6% 37.5 104.2%
541.leela_r 33.5 33.9 101.2% 34.2 102.1%
548.exchange2_r 65.4 76.6 117.1% 65.3 99.8%
557.xz_r 19.8 19.9 100.5% 19.9 100.5%
SPECrate..base 37.1 41.6 112.1% 37.3 100.5%
-----------------------------------------------------------------------
