It has been observed that trace reading thread runs on the same hw thread
most of the time during perf record sampling collection. This scheduling
layout leads up to 30% profiling overhead in case when some cpu intensive
workload fully utilizes a large server system with NUMA. Overhead usually
arises from remote (cross node) HW and memory references that have much
longer latencies than local ones [1].
This patch set implements --affinity option that lowers 30% overhead
completely for serial trace streaming (--affinity=cpu) and from 30% to
10% for AIO1 (--aio=1) trace streaming (--affinity=node|cpu).
See OVERHEAD section below for more details.
Implemented extension provides users with capability to instruct Perf
tool to bounce trace reading thread's affinity mask between NUMA nodes
(--affinity=node) or assign the thread to the exact cpu (--affinity=cpu)
that trace buffer being processed belongs to.
The extension brings improvement in case of full system utilization when
Perf tool process contends with workload process on cpu cores. In case a
system has free cores to execute Perf tool process during profiling the
default system scheduling layout induces the lowest overhead.
The patch set has been validated on BT benchmark from NAS Parallel
Benchmarks [2] running on dual socket, 44 cores, 88 hw threads Broadwell
system with kernels v4.4-21-generic (Ubuntu 16.04) and v4.20.0-rc5
(tip perf/core).
OVERHEAD:
BENCH REPORT BASED ELAPSED TIME BASED
v4.20.0-rc5
(tip perf/core):
(current) SERIAL-SYS / BASE : 1.27x (14.37/11.31), 1.29x (15.19/11.69)
SERIAL-NODE / BASE : 1.15x (13.04/11.31), 1.17x (13.79/11.69)
SERIAL-CPU / BASE : 1.00x (11.32/11.31), 1.01x (11.89/11.69)
AIO1-SYS / BASE : 1.29x (14.58/11.31), 1.29x (15.26/11.69)
AIO1-NODE / BASE : 1.08x (12.23/11.31), 1,11x (13.01/11.69)
AIO1-CPU / BASE : 1.07x (12.14/11.31), 1.08x (12.83/11.69)
v4.4.0-21-generic
(Ubuntu 16.04 LTS):
(current) SERIAL-SYS / BASE : 1.26x (13.73/10.87), 1.29x (14.69/11.32)
SERIAL-NODE / BASE : 1.19x (13.02/10.87), 1.23x (14.03/11.32)
SERIAL-CPU / BASE : 1.03x (11.21/10.87), 1.07x (12.18/11.32)
AIO1-SYS / BASE : 1.26x (13.73/10.87), 1.29x (14.69/11.32)
AIO1-NODE / BASE : 1.10x (12.04/10.87), 1.15x (13.03/11.32)
AIO1-CPU / BASE : 1.12x (12.20/10.87), 1.15x (13.09/11.32)
The patch set is generated for acme perf/core repository.
---
Alexey Budankov (3):
perf record: allocate affinity masks
perf record: apply affinity masks when reading mmap buffers
perf record: implement --affinity=node|cpu option
tools/perf/Documentation/perf-record.txt | 5 +++
tools/perf/builtin-record.c | 38 +++++++++++++++++++++-
tools/perf/perf.h | 5 +++
tools/perf/util/evlist.c | 10 ++++--
tools/perf/util/evlist.h | 2 +-
tools/perf/util/mmap.c | 40 +++++++++++++++++++++++-
tools/perf/util/mmap.h | 4 ++-
7 files changed, 97 insertions(+), 7 deletions(-)
---
[1] https://en.wikipedia.org/wiki/Non-uniform_memory_access
[2] https://www.nas.nasa.gov/publications/npb.html
[3] http://man7.org/linux/man-pages/man2/sched_setaffinity.2.html
[4] http://man7.org/linux/man-pages/man2/mbind.2.html
---
ENVIRONMENT AND MEASUREMENTS:
MACHINE:
broadwell, dual socket, 44 core, 88 threads
/proc/cpuinfo
processor : 87
vendor_id : GenuineIntel
cpu family : 6
model : 79
model name : Intel(R) Xeon(R) CPU E5-2699 v4 @ 2.20GHz
stepping : 1
microcode : 0xb000019
cpu MHz : 1200.117
cache size : 56320 KB
physical id : 1
siblings : 44
core id : 28
cpu cores : 22
apicid : 121
initial apicid : 121
fpu : yes
fpu_exception : yes
cpuid level : 20
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge
mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx
pdpe1gb rdtscp lm constant_tsc arch_perfmon pebs bts rep_good nopl xtopology
nonstop_tsc aperfmperf eagerfpu pni pclmulqdq dtes64 monitor ds_cpl vmx smx est
tm2 ssse3 sdbg fma cx16 xtpr pdcm pcid dca sse4_1 sse4_2 x2apic movbe popcnt
tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm 3dnowprefetch epb
intel_pt tpr_shadow vnmi flexpriority ept vpid fsgsbase tsc_adjust bmi1 hle
avx2 smep bmi2 erms invpcid rtm cqm rdseed adx smap xsaveopt cqm_llc
cqm_occup_llc cqm_mbm_total cqm_mbm_local dtherm ida arat pln pts
bugs :
bogomips : 4391.42
clflush size : 64
cache_alignment : 64
address sizes : 46 bits physical, 48 bits virtual
power management:
BASE:
/usr/bin/time ./bt.B.x
NAS Parallel Benchmarks (NPB3.3-OMP) - BT Benchmark
No input file inputbt.data. Using compiled defaults
Size: 102x 102x 102
Iterations: 200 dt: 0.0003000
Number of available threads: 88
BT Benchmark Completed.
Class = B
Size = 102x 102x 102
Iterations = 200
Time in seconds = 10.87
Total threads = 88
Avail threads = 88
Mop/s total = 64608.74
Mop/s/thread = 734.19
Operation type = floating point
Verification = SUCCESSFUL
Version = 3.3.1
Compile date = 20 Sep 2018
956.25user 19.14system 0:11.32elapsed 8616%CPU (0avgtext+0avgdata
210496maxresident)k
0inputs+0outputs (0major+57939minor)pagefaults 0swaps
SERIAL-SYS:
/usr/bin/time ./tip/tools/perf/perf record -v -N -B -T -R -F 25000 -a
-e cycles -- ./bt.B.x
Using CPUID GenuineIntel-6-4F-1
nr_cblocks: 0
affinity (UNSET:0, NODE:1, CPU:2) = 0
mmap size 528384B
NAS Parallel Benchmarks (NPB3.3-OMP) - BT Benchmark
No input file inputbt.data. Using compiled defaults
Size: 102x 102x 102
Iterations: 200 dt: 0.0003000
Number of available threads: 88
BT Benchmark Completed.
Class = B
Size = 102x 102x 102
Iterations = 200
Time in seconds = 13.73
Total threads = 88
Avail threads = 88
Mop/s total = 51136.52
Mop/s/thread = 581.10
Operation type = floating point
Verification = SUCCESSFUL
Version = 3.3.1
Compile date = 20 Sep 2018
[ perf record: Captured and wrote 1661,120 MB perf.data ]
1184.84user 40.70system 0:14.69elapsed 8341%CPU (0avgtext+0avgdata
208612maxresident)k
0inputs+3402072outputs (0major+137077minor)pagefaults 0swaps
SERIAL-NODE:
/usr/bin/time ./tip/tools/perf/perf record -v -N -B -T -R -F 25000
--affinity=node -a -e cycles -- ./bt.B.x
Using CPUID GenuineIntel-6-4F-1
nr_cblocks: 0
affinity (UNSET:0, NODE:1, CPU:2) = 1
mmap size 528384B
NAS Parallel Benchmarks (NPB3.3-OMP) - BT Benchmark
No input file inputbt.data. Using compiled defaults
Size: 102x 102x 102
Iterations: 200 dt: 0.0003000
Number of available threads: 88
BT Benchmark Completed.
Class = B
Size = 102x 102x 102
Iterations = 200
Time in seconds = 13.02
Total threads = 88
Avail threads = 88
Mop/s total = 53924.69
Mop/s/thread = 612.78
Operation type = floating point
Verification = SUCCESSFUL
Version = 3.3.1
Compile date = 20 Sep 2018
[ perf record: Captured and wrote 1557,152 MB perf.data ]
1120.42user 29.92system 0:14.03elapsed 8198%CPU (0avgtext+0avgdata
206388maxresident)k
0inputs+3189128outputs (0major+149207minor)pagefaults 0swaps
SERIAL-CPU:
/usr/bin/time ./tip/tools/perf/perf record -v -N -B -T -R -F 25000
--affinity=cpu -a -e cycles -- ./bt.B.x
Using CPUID GenuineIntel-6-4F-1
nr_cblocks: 0
affinity (UNSET:0, NODE:1, CPU:2) = 2
mmap size 528384B
NAS Parallel Benchmarks (NPB3.3-OMP) - BT Benchmark
No input file inputbt.data. Using compiled defaults
Size: 102x 102x 102
Iterations: 200 dt: 0.0003000
Number of available threads: 88
BT Benchmark Completed.
Class = B
Size = 102x 102x 102
Iterations = 200
Time in seconds = 11.21
Total threads = 88
Avail threads = 88
Mop/s total = 62642.24
Mop/s/thread = 711.84
Operation type = floating point
Verification = SUCCESSFUL
Version = 3.3.1
Compile date = 20 Sep 2018
[ perf record: Captured and wrote 1365,043 MB perf.data ]
976.06user 31.35system 0:12.18elapsed 8264%CPU (0avgtext+0avgdata
208488maxresident)k
0inputs+2795704outputs (0major+126032minor)pagefaults 0swaps
AIO1-SYS:
/usr/bin/time ./tip/tools/perf/perf record -v -N -B -T -R -F 25000
--aio=1 -a -e cycles -- ./bt.B.x
Using CPUID GenuineIntel-6-4F-1
nr_cblocks: 1
affinity (UNSET:0, NODE:1, CPU:2) = 0
mmap size 528384B
NAS Parallel Benchmarks (NPB3.3-OMP) - BT Benchmark
No input file inputbt.data. Using compiled defaults
Size: 102x 102x 102
Iterations: 200 dt: 0.0003000
Number of available threads: 88
BT Benchmark Completed.
Class = B
Size = 102x 102x 102
Iterations = 200
Time in seconds = 14.23
Total threads = 88
Avail threads = 88
Mop/s total = 49338.27
Mop/s/thread = 560.66
Operation type = floating point
Verification = SUCCESSFUL
Version = 3.3.1
Compile date = 20 Sep 2018
[ perf record: Captured and wrote 1720,590 MB perf.data ]
1229.19user 41.99system 0:15.22elapsed 8350%CPU (0avgtext+0avgdata
208604maxresident)k
0inputs+3523880outputs (0major+124670minor)pagefaults 0swaps
AIO1-NODE:
/usr/bin/time ./tip/tools/perf/perf record -v -N -B -T -R -F 25000
--aio=1 --affinity=node -a -e cycles -- ./bt.B.x
Using CPUID GenuineIntel-6-4F-1
nr_cblocks: 1
affinity (UNSET:0, NODE:1, CPU:2) = 1
mmap size 528384B
NAS Parallel Benchmarks (NPB3.3-OMP) - BT Benchmark
No input file inputbt.data. Using compiled defaults
Size: 102x 102x 102
Iterations: 200 dt: 0.0003000
Number of available threads: 88
BT Benchmark Completed.
Class = B
Size = 102x 102x 102
Iterations = 200
Time in seconds = 12.04
Total threads = 88
Avail threads = 88
Mop/s total = 58313.58
Mop/s/thread = 662.65
Operation type = floating point
Verification = SUCCESSFUL
Version = 3.3.1
Compile date = 20 Sep 2018
[ perf record: Captured and wrote 1471,279 MB perf.data ]
1055.62user 30.43system 0:13.03elapsed 8333%CPU (0avgtext+0avgdata
208424maxresident)k
0inputs+3013288outputs (0major+79088minor)pagefaults 0swaps
AIO1-CPU:
/usr/bin/time ./tip/tools/perf/perf record -v -N -B -T -R -F 25000
--aio=1 --affinity=cpu -a -e cycles -- ./bt.B.x
Using CPUID GenuineIntel-6-4F-1
nr_cblocks: 1
affinity (UNSET:0, NODE:1, CPU:2) = 2
mmap size 528384B
NAS Parallel Benchmarks (NPB3.3-OMP) - BT Benchmark
No input file inputbt.data. Using compiled defaults
Size: 102x 102x 102
Iterations: 200 dt: 0.0003000
Number of available threads: 88
BT Benchmark Completed.
Class = B
Size = 102x 102x 102
Iterations = 200
Time in seconds = 12.20
Total threads = 88
Avail threads = 88
Mop/s total = 57538.84
Mop/s/thread = 653.85
Operation type = floating point
Verification = SUCCESSFUL
Version = 3.3.1
Compile date = 20 Sep 2018
[ perf record: Captured and wrote 1486,859 MB perf.data ]
1051.97user 42.07system 0:13.09elapsed 8352%CPU (0avgtext+0avgdata
206388maxresident)k
0inputs+3045168outputs (0major+174612minor)pagefaults 0swaps
