https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110832
Bug ID: 110832
Summary: 14% capacita -O2 regression between g:9fdbd7d6fa5e0a76
(2023-07-26 01:45) and g:ca912a39cccdd990 (2023-07-27
03:44) on zen3 and core
Product: gcc
Version: 13.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: middle-end
Assignee: unassigned at gcc dot gnu.org
Reporter: hubicka at gcc dot gnu.org
Target Milestone: ---
Biggest regression is seen here
https://lnt.opensuse.org/db_default/v4/CPP/graph?plot.0=466.758.0
zen3
https://lnt.opensuse.org/db_default/v4/CPP/graph?plot.0=466.758.0
Curiously zen2 improves:
https://lnt.opensuse.org/db_default/v4/CPP/graph?plot.0=171.758.0
I can see instruction count differnece in perfs:
Performance counter stats for './a.out':
10923.70 msec task-clock:u # 1.000 CPUs
utilized
0 context-switches:u # 0.000 /sec
0 cpu-migrations:u # 0.000 /sec
15510 page-faults:u # 1.420 K/sec
59062937176 cycles:u # 5.407 GHz
(83.33%)
12607081 stalled-cycles-frontend:u # 0.02% frontend
cycles idle (83.34%)
122404896 stalled-cycles-backend:u # 0.21% backend
cycles idle (83.34%)
112648123380 instructions:u # 1.91 insn per
cycle
# 0.00 stalled cycles per
insn (83.34%)
9666338531 branches:u # 884.896 M/sec
(83.34%)
2937216 branch-misses:u # 0.03% of all
branches (83.31%)
10.924108973 seconds time elapsed
10.912056000 seconds user
0.012000000 seconds sys
Performance counter stats for './b.out':
11025.38 msec task-clock:u # 1.000 CPUs
utilized
0 context-switches:u # 0.000 /sec
0 cpu-migrations:u # 0.000 /sec
14998 page-faults:u # 1.360 K/sec
59436352848 cycles:u # 5.391 GHz
(83.31%)
9217660 stalled-cycles-frontend:u # 0.02% frontend
cycles idle (83.32%)
210162784 stalled-cycles-backend:u # 0.35% backend
cycles idle (83.35%)
131604240004 instructions:u # 2.21 insn per
cycle
# 0.00 stalled cycles per
insn (83.35%)
9657712171 branches:u # 875.953 M/sec
(83.35%)
3146487 branch-misses:u # 0.03% of all
branches (83.33%)
11.025701172 seconds time elapsed
11.005646000 seconds user
0.020002000 seconds sys
however perf report does not show clear differences in times of functions.
I
