0-Day CI Linux Kernel Performance Report (V5.14)

Published: 10/09/2021

By Beibei Si

Introduction

0-Day CI is an automated Linux kernel test service that provides comprehensive test coverage of the Linux kernel. It covers kernel build, static analysis, boot, functional, performance and power tests. This report shows the recent observations of kernel performance status on IA platform based on the test results from 0-Day CI service. It is structured in the following manner:

  • Section 2, test parameter description
  • Section 3, merged regressions and improvements in v5.14 release candidates
  • Section 4, captured regressions and improvements by shift-left testing during developers’ and maintainers’ tree during v5.14 release cycle
  • Section 5, performance comparison among different kernel releases
  • Section 6, test machine list

Test Parameters Descriptions

Here are the descriptions for each parameter/field used in the tests.

Classification Name Description
General runtime Run the test case within a certain time period (seconds or minutes)
  nr_task If it is an integer, which means the number of processes/threads (to run the workload) of this job. Default is 1.

If it is a percentage, e.g. 200% means the number of processes/threads is double of cpu number
  nr_threads Alias of nr_task
  iterations Number to repeat this job
  test_size Test disk size or memory size
  set_nic_irq_affinity Set NIC interrupt affinity
  disable_latency_stats Latency_stats may introduce too much noise if there are too many context switches, allow to disable it
  transparent_hugepage Set transparent hugepage policy (/sys/kernel/mm/transparent_hugepage)
  boot_params:bp1_memmap Boot parameters of memmap
  disk:nr_pmem number of pmem partitions used by test
  swap:priority Priority means the priority of the swap device. priority is a value between -1 and 32767, the default is -1 and higher priority with higher value.
Test Machine model Name of Intel processor microarchitecture
  brand Brand name of cpu
  cpu_number Number of cpu
  memory Size of memory

Linux Kernel V5.14 Release Test

Linus has released the 5.14 kernel, and mentioned “So I realize you must all still be busy with all the galas and fancy balls and all the other 30th anniversary events, but at some point you must be getting tired of the constant glitz, the fireworks, and the champagne. That ball gown or tailcoat isn't the most comfortable thing, either. The celebrations will go on for a few more weeks yet, but you all may just need a breather from them. And when that happens, I have just the thing for you - a new kernel release to test and enjoy.” Headline features in 5.14 include: core scheduling (at last), the burstable CFS bandwidth controller, some initial infrastructure for BPF program loaders, the rq_qos I/O priority policy, some improvements to the SO_REUSEPORT networking option, the control-group "kill" button, the memfd_secret() system call, the quotactl_fd() system call, and much more. See the LWN merge-window summaries (part 1part 2) for more details.

0-Day CI monitored the release closely to trace down the performance status on IA platform. 0-Day observed 9 regressions and 7 improvements during feature development phase for v5.14. We will share more detailed information together with correlated patches that led to the results. Note that the assessment is limited by the test coverage 0-Day has now. The list is summarized in the observation summary section.

Observation Summary

0-Day CI observed 9 regressions and 7 improvements during the feature development phase for v5.14, which is in the time frame from v5.14-rc1 to v5.14 release.

Test Indicator Mail Test Scenario Test Machine Development Base Status
fsmark.files_per_sec [xfs] a79b28c284: -4.6% regression iterations: 1x

nr_threads: 32t

disk: 1SSD

fs: xfs

filesize: 8K

test_size: 400M

sync_method: fsyncBeforeClose

nr_directories: 16d

nr_files_per_directory: 256fpd

cpufreq_governor: performance
lkp-csl-2sp7 v5.13-rc4 merged at v5.14-rc1, no response from author yet
stress-ng.loop.ops_per_sec [pipe] 3a34b13a88: -12.6% regression nr_threads: 100%

iterations: 4

mode: process

ipc: pipe

cpufreq_governor: performance
lkp-icl-2sp1 v5.14-rc3 merged at v5.14-rc4, author accepted the regression and thought it’s expected
stress-ng.fallocate.ops_per_sec [xfs] eef983ffea: -15.2% regression nr_threads: 10%

disk: 1HDD

testtime: 60s

fs: xfs

class: filesystem

test: fallocate

cpufreq_governor: performance
lkp-csl-2sp7 v5.13-rc4 merged at v5.14-rc1, no response from author, but the regression was gone in v5.14
tbench.throughput-MB/sec [xfs] bad77c375e: -10.0% regression nr_threads: 10%

disk: 1HDD

testtime: 60s

fs: xfs

class: filesystem

test: fallocate

cpufreq_governor: performance
lkp-csl-2sp7 v5.13-rc4 merged at v5.14-rc1, no response from author yet
stress-ng.link.ops_per_sec [btrfs] ecc64fab7d: -81.7% regression nr_threads: 10%

disk: 1HDD

testtime: 60s

fs: btrfs

class: filesystem

test: link

cpufreq_governor: performance
lkp-csl-2sp7 v5.13-rc4 merged at v5.14-rc4, author accepted the regression and sent out a fixed patch 6e3688e66f2f, regression recovered to +443.3%
stress-ng.lockbus.ops_per_sec [clocksource] db3a34e174: -10.1% regression nr_threads: 100%

testtime: 60s

class: cpu-cache

test: lockbus

cpufreq_governor: performance
lkp-csl-2sp7 v5.13-rc4 merged at v5.14-rc1, no response from author but 0-Day CI team is following up
stress-ng.mknod.ops_per_sec [xfs] 2bf1ec0ff0: -45.4% regression nr_threads: 10%

disk: 1HDD

testtime: 60s

fs: xfs

class: filesystem

test: mknod

cpufreq_governor: performance
lkp-csl-2sp7 v5.14-rc1 merged at v5.14-rc4, no response from author but 0-Day team thought it’s acceptable
stress-ng.sigio.ops_per_sec [pipe] 3b844826b6: -99.3% regression nr_threads: 100%

disk: 1HDD

testtime: 60s

class: interrupt

test: sigio

cpufreq_governor: performance
lkp-csl-2sp7 v5.14-rc6 merged at v5.14-rc7, author accepted the regression, Linus sent out a fixed patch fe67f4dd8daa, merged at v5.14
will-it-scale.per_process_ops [mm/memcg] 5387c90490: -21.3% regression nr_task: 50%

mode: process

test: unix1

cpufreq_governor: performance
lkp-skl-fpga01 v5.13 merged at v5.14-rc1, no response from author but 0-Day CI team is following up
Improvement          
fio.write_iops [sched] 9edeaea1bc: 4.7% improvement disk: 2pmem

fs: xfs

mount_option: dax

runtime: 200s

nr_task: 50%

time_based: tb

rw: write

bs: 2M

ioengine: mmap

test_size: 200G

cpufreq_governor: performance
lkp-csl-2sp6 v5.13-rc1 merged at v5.14-rc1
aim9.sync_disk_rw.ops_per_sec [io] 49e7f0c789: 6.5% improvement disk: 1SSD

fs: btrfs

runtime: 300s

nr_task: 8

rw: randwrite

bs: 4k

ioengine: io_uring

test_size: 256g

cpufreq_governor: performance
lkp-csl-2ap1 v5.14-rc1 merged at v5.14-rc6
hackbench.throughput [mm/memcg] 5387c90490: 41.3% improvement nr_threads: 100%

iterations: 4

mode: threads

ipc: socket

cpufreq_governor: performance
lkp-skl-fpga01 v5.13 merged at v5.14-rc1
stress-ng.fanotify.ops_per_sec [mm/memcg] 68ac5b3c8d: 42.4% improvement nr_threads: 100%

iterations: 4

mode: threads

ipc: socket

cpufreq_governor: performance
lkp-csl-2ap4 v5.13 merged at v5.14-rc1
netperf.Throughput_tps [iommu/vt] e93a67f5a0: 28.9% improvement ip: ipv4

runtime: 300s

nr_threads: 16

cluster: cs-localhost

test: TCP_CRR

cpufreq_governor: performance
lkp-csl-2ap3 v5.13-rc4 merged at v5.14-rc1
stress-ng.msg.ops_per_sec [trace] 3d3d9c072e: 18.5% improvement nr_threads: 10%

disk: 1HDD

testtime: 60s

fs: ext4

class: os

test: msg

cpufreq_governor: performance
lkp-csl-2sp5 v5.13-rc5 merged at v5.14-rc1
will-it-scale.per_thread_ops [kprobes] ec6aba3d2b: 3.8% improvement nr_task: 100%

mode: thread

test: getppid1
cpufreq_governor: performance
lkp-csl-2sp9 v5.13-rc1 merged at v5.14-rc1

Shift-left Testing

Beyond testing trees in the upstream kernel, 0-Day CI also tests developers’ and maintainers’ trees, which can catch issues earlier and reduce wider impact. We call it “shift-left” testing. During the v5.14 release cycle, 0-Day CI had reported 9 major performance regressions and 8 major improvements by doing shift-left testing. We will share more detailed information together with possible code changes that led to this result for some of these, though the assessment is limited by the test coverage we have now. The whole list is summarized in the report summary section.

Report Summary

0-Day CI had reported 9 performance regressions and 8 improvements by doing shift-left testing on developer and maintainer repos.

Test Indicator Mail Test Scenario Test Machine Status
aim7.jobs-per-min [xfs] 6df693ed7b: -15.7% regression disk: 4BRD_12G

md: RAID1

fs: xfs

test: disk_wrt

load: 3000

cpufreq_governor: performance
lkp-csl-2sp9 currently not merged, author accepted the regression and 0-Day CI team is working with the author to fix it
aim7.jobs-per-min [memcg] 45208c9105: -14.0% regression disk: 1BRD_48G

fs: xfs

test: disk_rr

load: 3000

cpufreq_governor: performance
lkp-icl-2sp2 currently not merged, author accepted the regression and is inprogress to fix it
fxmark.hdd_ext4_no_jnl_DWTL_1_directio.works/sec [loop] 2112f5c133: -49.6% regression disk: 1HDD

media: hdd

test: DWTL

fstype: ext4_no_jnl

directio: directio

cpufreq_governor: performance
lkp-knm02 merged at v5.15-rc1, no response from author yet
netperf.Throughput_tps [bpf] b89fbfbb85: -21.3% regression ip: ipv4

runtime: 300s

nr_threads: 16

cluster: cs-

localhost test: TCP_CRR
cpufreq_governor: performance
lkp-csl-2ap3 merged at v5.15-rc1, author couldn't reproduce in his environment, 0-Day CI team is following up
stress-ng.memhotplug.ops_per_sec [mm/migrate] 9eeb73028c: -53.8% regression 10%-1HDD-60s-ext4-os-memhotplug-performance-ucode=0x5003006 lkp-csl-2sp5 currently not merged, author accepted the regression, and 0-Day CI team is working with the author to fix it
will-it-scale.per_process_ops [memcg] 059dd9003a: -39.8% regression nr_task: 100%

mode: process

test: lock1

cpufreq_governor: performance
lkp-icl-2sp1 currently not merged, no response from author yet
will-it-scale.per_process_ops [memcg] 0f12156dff: -33.6% regression nr_task: 50%

mode: process

test: lock1

cpufreq_governor: performance
lkp-skl-fpga01 merged at v5.15-rc1, author accepted the regression and the patch was reverted on latest kernel tree
will-it-scale.per_thread_ops [posix] 63a17eea7d: -43.8% regression nr_task: 100%

mode: thread

test: lseek1

cpufreq_governor: performance
lkp-skl-fpga01 currently not merged, no response from author yet
will-it-scale.per_thread_ops [memcg] fa4e6b1ad5: -15.4% regression nr_task: 50%

mode: thread

test: poll2

cpufreq_governor: performance
lkp-hsw-4ex1 currently not merged, no response from author yet

 

Improvement        
aim7.jobs-per-min [ext4] cc883236b7: 69.4% improvement disk: 4BRD_12G

md: RAID0

fs: ext4

test: disk_rw

load: 3000

cpufreq_governor: performance
lkp-csl-2sp9 currently not merged
filebench.sum_operations/s [sched] 260916b537: 5.6% improvement disk: 1HDD

fs: f2fs

test: filemicro_writefsync.f

cpufreq_governor: performance
lkp-knm02 currently not merged
fsmark.files_per_sec [SUNRPC] e38b3f2005: 1857.1% improvement iterations: 1x

nr_threads: 1t

disk: 1BRD_48G

fs: f2fs

fs2: nfsv4

filesize: 4M

test_size: 24G

sync_method: NoSync

cpufreq_governor: performance
lkp-csl-2ap2 merged at v5.15-rc1
stress-ng.link.ops_per_sec [btrfs] 6e3688e66f: 443.3% improvement nr_threads: 10%

disk: 1HDD

testtime: 60s

fs: btrfs

class: filesystem

test: link

cpufreq_governor: performance
lkp-csl-2sp7 currently not merged
stress-ng.loop.ops_per_sec [loop] 8883efd909: 148.4% improvement nr_threads: 100%

disk: 1HDD

testtime: 60s

class: device

test: loop

cpufreq_governor: performance
lkp-csl-2sp7 currently not merged
stress-ng.loop.ops_per_sec [loop] acd1746478: 140.9% improvement nr_threads: 100%

disk: 1HDD

testtime: 60s

class: device

test: loop

cpufreq_governor: performance
lkp-csl-2sp7 currently not merged
stress-ng.netdev.ops_per_sec [net] b0e99d0377: 7.7% improvement nr_threads: 100%

testtime: 60s

class: network

test: netdev

cpufreq_governor: performance
lkp-csl-2sp5 merged at v5.15-rc1
will-it-scale.per_thread_ops [fsnotify] e43de7f086: 10.2% improvement nr_task: 100%

mode: thread

test: eventfd1

cpufreq_governor: performance
lkp-csl-2ap2 merged at v5.15-rc1

Test Machines

IVB DESKTOP

model Ivy Bridge
brand Intel® Core™ i3-3220 CPU @ 3.30GHz
cpu number 8
memory 16G

 

model Ivy Bridge
brand Intel® Core™ i3-3220 CPU @ 3.30GHz
cpu number 4
memory 8G

SKL SP

model Skylake
brand Intel® Xeon® CPU E5-2697 v2 @ 2.70GHz
cpu number 80
memory 64G

BDW EP

model Broadwell-EP
brand Intel® Xeon® CPU E5-2699 v4 @ 2.20GHz
cpu number 88
memory 128G

HSW EP

model Haswell-EP
brand Intel® Xeon® CPU E5-2699 v3 @ 2.30GHz
cpu number 72
memory 128G

IVB EP

model Ivy Bridge-EP
brand Intel® Xeon® CPU E5-2690 v2 @ 3.00GHz
cpu number 40
memory 384G

 

model Ivytown Ivy Bridge-EP
brand Intel® Xeon® CPU E5-2697 v2 @ 2.70GHz
cpu number 48
memory 64G

HSX EX

model Brickland Haswell-EX
brand Intel® Xeon® CPU E7-8890 v3 @ 2.50GHz
cpu number 144
memory 512G

Product and Performance Information

1

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.