Re: [RFC PATCH v2 0/2] sched/fair: Choose the CPU where short task is running during wake up
From: K Prateek Nayak
Date: Tue Nov 22 2022 - 05:37:11 EST
Hello Chenyu,
I've tested v2 series on an dual socket Zen3 system (2 x 64C/128T) and
the results are largely positive.
tl;dr
o Hackbench results are mostly similar with tip.
o schbench sees improvements to tail latency when the system is
loaded in NPS1 case but I do see one small regression for
128 workers in NPS4 mode.
o tbench sees small gains in NPS2 and NPS4 mode
o Stream and Spec-JBB results remain same as the tip.
o ycsb-mongodb sees small gains in NPS2 and NPS4 mode.
o unixbench results see small to moderate gains overall.
I'll leave the detailed results below:
Following are the results from running standard benchmarks on a
dual socket Zen3 (2 x 64C/128T) machine configured in different
NPS modes.
NPS Modes are used to logically divide single socket into
multiple NUMA region.
Following is the NUMA configuration for each NPS mode on the system:
NPS1: Each socket is a NUMA node.
Total 2 NUMA nodes in the dual socket machine.
Node 0: 0-63, 128-191
Node 1: 64-127, 192-255
NPS2: Each socket is further logically divided into 2 NUMA regions.
Total 4 NUMA nodes exist over 2 socket.
Node 0: 0-31, 128-159
Node 1: 32-63, 160-191
Node 2: 64-95, 192-223
Node 3: 96-127, 223-255
NPS4: Each socket is logically divided into 4 NUMA regions.
Total 8 NUMA nodes exist over 2 socket.
Node 0: 0-15, 128-143
Node 1: 16-31, 144-159
Node 2: 32-47, 160-175
Node 3: 48-63, 176-191
Node 4: 64-79, 192-207
Node 5: 80-95, 208-223
Node 6: 96-111, 223-231
Node 7: 112-127, 232-255
Benchmark Results:
Kernel versions:
- tip: 5.19.0 tip sched/core
- sis_short: 5.19.0 tip sched/core + this series
When we started testing, the tip was at:
commit fdf756f71271 ("sched: Fix more TASK_state comparisons")
~~~~~~~~~~~~~
~ hackbench ~
~~~~~~~~~~~~~
o NPS1
Test: tip sis_short
1-groups: 4.06 (0.00 pct) 4.02 (0.98 pct)
2-groups: 4.76 (0.00 pct) 4.71 (1.05 pct)
4-groups: 5.22 (0.00 pct) 5.07 (2.87 pct)
8-groups: 5.35 (0.00 pct) 5.31 (0.74 pct)
16-groups: 7.21 (0.00 pct) 7.22 (-0.13 pct)
o NPS2
Test: tip sis_short
1-groups: 4.09 (0.00 pct) 4.05 (0.97 pct)
2-groups: 4.70 (0.00 pct) 4.69 (0.21 pct)
4-groups: 5.05 (0.00 pct) 4.95 (1.98 pct)
8-groups: 5.35 (0.00 pct) 5.27 (1.49 pct)
16-groups: 6.37 (0.00 pct) 6.60 (-3.61 pct)
o NPS4
Test: tip sis_short
1-groups: 4.07 (0.00 pct) 4.13 (-1.47 pct)
2-groups: 4.65 (0.00 pct) 4.71 (-1.29 pct)
4-groups: 5.13 (0.00 pct) 5.05 (1.55 pct)
8-groups: 5.47 (0.00 pct) 5.44 (0.54 pct)
16-groups: 6.82 (0.00 pct) 6.72 (1.46 pct)
~~~~~~~~~~~~
~ schbench ~
~~~~~~~~~~~~
o NPS1
#workers: tip sis_short
1: 33.00 (0.00 pct) 34.00 (-3.03 pct)
2: 35.00 (0.00 pct) 36.00 (-2.85 pct)
4: 39.00 (0.00 pct) 40.00 (-2.56 pct)
8: 49.00 (0.00 pct) 47.00 (4.08 pct)
16: 63.00 (0.00 pct) 64.00 (-1.58 pct)
32: 109.00 (0.00 pct) 106.00 (2.75 pct)
64: 208.00 (0.00 pct) 214.00 (-2.88 pct)
128: 559.00 (0.00 pct) 497.00 (11.09 pct)
256: 45888.00 (0.00 pct) 47424.00 (-3.34 pct)
512: 80000.00 (0.00 pct) 77952.00 (2.56 pct)
o NPS2
#workers: tip sis_short
1: 30.00 (0.00 pct) 31.00 (-3.33 pct)
2: 37.00 (0.00 pct) 36.00 (2.70 pct)
4: 39.00 (0.00 pct) 40.00 (-2.56 pct)
8: 51.00 (0.00 pct) 50.00 (1.96 pct)
16: 67.00 (0.00 pct) 67.00 (0.00 pct)
32: 117.00 (0.00 pct) 114.00 (2.56 pct)
64: 216.00 (0.00 pct) 214.00 (0.92 pct)
128: 529.00 (0.00 pct) 597.00 (-12.85 pct) *
128: 388.00 (0.00 pct) 382.00 (1.54 pct) [Verification Run]
256: 47040.00 (0.00 pct) 47424.00 (-0.81 pct)
512: 84864.00 (0.00 pct) 81792.00 (3.61 pct)
o NPS4
#workers: tip sis_short
1: 23.00 (0.00 pct) 33.00 (-43.47 pct)
2: 28.00 (0.00 pct) 27.00 (3.57 pct)
4: 41.00 (0.00 pct) 37.00 (9.75 pct)
8: 60.00 (0.00 pct) 56.00 (6.66 pct)
16: 71.00 (0.00 pct) 71.00 (0.00 pct)
32: 117.00 (0.00 pct) 114.00 (2.56 pct)
64: 227.00 (0.00 pct) 218.00 (3.96 pct)
128: 545.00 (0.00 pct) 747.00 (-37.06 pct) *
128: 383.00 (0.00 pct) 412.00 (-7.85 pct) [Verification Run]
256: 45632.00 (0.00 pct) 47296.00 (-3.64 pct)
512: 81024.00 (0.00 pct) 78720.00 (2.84 pct)
Note: For lower worker count, schbench can show run to
run variation depending on external factors. Regression
for lower worker count can be ignored. The results are
included to spot any large blow up in the tail latency
for larger worker count.
~~~~~~~~~~
~ tbench ~
~~~~~~~~~~
o NPS1
Clients: tip sis_short
1 578.37 (0.00 pct) 568.72 (-1.66 pct)
2 1062.09 (0.00 pct) 1055.45 (-0.62 pct)
4 1800.62 (0.00 pct) 1833.37 (1.81 pct)
8 3211.02 (0.00 pct) 3124.95 (-2.68 pct)
16 4848.92 (0.00 pct) 4823.27 (-0.52 pct)
32 9091.36 (0.00 pct) 9301.80 (2.31 pct)
64 15454.01 (0.00 pct) 14639.52 (-5.27 pct) *
64 14890.79 (0.00 pct) 14314.95 (-3.86 pct) [Verification Run]
128 3511.33 (0.00 pct) 2740.46 (-21.95 pct) *
128 19750.19 (0.00 pct) 20006.42 (1.29 pct) [Verification Run]
256 50019.32 (0.00 pct) 50384.18 (0.72 pct)
512 44317.68 (0.00 pct) 44155.90 (-0.36 pct)
1024 41200.85 (0.00 pct) 41242.49 (0.10 pct)
o NPS2
Clients: tip sis_short
1 576.05 (0.00 pct) 578.08 (0.35 pct)
2 1037.68 (0.00 pct) 1098.68 (5.87 pct)
4 1818.13 (0.00 pct) 1838.79 (1.13 pct)
8 3004.16 (0.00 pct) 3071.73 (2.24 pct)
16 4520.11 (0.00 pct) 4820.67 (6.64 pct)
32 8624.23 (0.00 pct) 9264.14 (7.41 pct)
64 14886.75 (0.00 pct) 14976.91 (0.60 pct)
128 20602.00 (0.00 pct) 20247.46 (-1.72 pct)
256 45566.83 (0.00 pct) 48786.00 (7.06 pct)
512 42717.49 (0.00 pct) 44678.97 (4.59 pct)
1024 40936.61 (0.00 pct) 40866.32 (-0.17 pct)
o NPS4
Clients: tip sis_short
1 576.36 (0.00 pct) 588.43 (2.09 pct)
2 1044.26 (0.00 pct) 1074.47 (2.89 pct)
4 1839.77 (0.00 pct) 1852.10 (0.67 pct)
8 3043.53 (0.00 pct) 3235.32 (6.30 pct)
16 5207.54 (0.00 pct) 4804.41 (-7.74 pct) *
16 4620.29 (0.00 pct) 4714.69 (2.04 pct) [Verification Run]
32 9263.86 (0.00 pct) 8238.55 (-11.06 pct) *
32 9263.86 (0.00 pct) 9443.77 (1.94 pct) [Verification Run]
64 14959.66 (0.00 pct) 15321.44 (2.41 pct)
128 20698.65 (0.00 pct) 16806.27 (-18.80 pct) *
128 20698.65 (0.00 pct) 20978.42 (1.35 pct) [Verification Run]
256 46666.21 (0.00 pct) 49787.15 (6.68 pct)
512 41532.80 (0.00 pct) 44738.18 (7.71 pct)
1024 39459.49 (0.00 pct) 41473.96 (5.10 pct)
Note: On the tested kernel, with 128 clients, tbench can
run into a bottleneck during C2 exit. More details can be
found at:
https://lore.kernel.org/lkml/20220921063638.2489-1-kprateek.nayak@xxxxxxx/
This issue has been fixed in v6.0 but was not part of the
tip kernel when I started testing. This data point has
been rerun with C2 disabled to get representative results.
~~~~~~~~~~
~ stream ~
~~~~~~~~~~
o NPS1
- 10 Runs:
Test: tip sis_short
Copy: 328419.14 (0.00 pct) 336740.00 (2.53 pct)
Scale: 206071.21 (0.00 pct) 212682.17 (3.20 pct)
Add: 235271.48 (0.00 pct) 244104.35 (3.75 pct)
Triad: 253175.80 (0.00 pct) 251776.26 (-0.55 pct)
- 100 Runs:
Test: tip sis_short
Copy: 328209.61 (0.00 pct) 340132.12 (3.63 pct)
Scale: 216310.13 (0.00 pct) 218811.70 (1.15 pct)
Add: 244417.83 (0.00 pct) 246349.22 (0.79 pct)
Triad: 237508.83 (0.00 pct) 260160.20 (9.53 pct)
o NPS2
- 10 Runs:
Test: tip sis_short
Copy: 336503.88 (0.00 pct) 319171.80 (-5.15 pct)
Scale: 218035.23 (0.00 pct) 219061.13 (0.47 pct)
Add: 257677.42 (0.00 pct) 256776.22 (-0.34 pct)
Triad: 268872.37 (0.00 pct) 263751.14 (-1.90 pct)
- 100 Runs:
Test: tip sis_short
Copy: 332304.34 (0.00 pct) 320547.46 (-3.53 pct)
Scale: 223421.60 (0.00 pct) 220418.63 (-1.34 pct)
Add: 252363.56 (0.00 pct) 254553.30 (0.86 pct)
Triad: 266687.56 (0.00 pct) 260009.00 (-2.50 pct)
o NPS4
- 10 Runs:
Test: tip sis_short
Copy: 353515.62 (0.00 pct) 338973.78 (-4.11 pct)
Scale: 228854.37 (0.00 pct) 230319.08 (0.64 pct)
Add: 254942.12 (0.00 pct) 247794.21 (-2.80 pct)
Triad: 270521.87 (0.00 pct) 261432.32 (-3.36 pct)
- 100 Runs:
Test: tip sis_short
Copy: 374520.81 (0.00 pct) 363272.21 (-3.00 pct)
Scale: 246280.23 (0.00 pct) 241457.83 (-1.95 pct)
Add: 262772.72 (0.00 pct) 261924.44 (-0.32 pct)
Triad: 283740.92 (0.00 pct) 274791.15 (-3.15 pct)
~~~~~~~~~~~~~~~~~
~ Spec-JBB NPS1 ~
~~~~~~~~~~~~~~~~~
--------------------------------------------------
| Throughput | tip | sis_short |
--------------------------------------------------
| Max-jOPS | 100% | 98.84% |
| Critical-jOPS | 100% | 100.31% |
--------------------------------------------------
~~~~~~~~~~~~~~~~
~ ycsb-mongodb ~
~~~~~~~~~~~~~~~~
o NPS1
tip: 131696.33 (var: 2.03%)
sis_short: 130844.67 (var: 2.55%) (-0.64%)
o NPS2:
tip: 129895.33 (var: 2.34%)
sis_short: 133104.33 (var: 1.65%) (+2.647%)
o NPS4:
tip: 131165.00 (var: 1.06%)
sis_short: 138180.67 (var: 0.83%) (+5.34%)
~~~~~~~~~~~~~
~ unixbench ~
~~~~~~~~~~~~~
-> unixbench-dhry2reg
o NPS1
kernel: tip sis_short
Min unixbench-dhry2reg-1 48876615.50 ( 0.00%) 48489507.40 ( -0.79%)
Min unixbench-dhry2reg-512 6260344658.90 ( 0.00%) 6253084311.60 ( -0.12%)
Hmean unixbench-dhry2reg-1 49299721.81 ( 0.00%) 49014780.04 ( -0.58%)
Hmean unixbench-dhry2reg-512 6267459427.19 ( 0.00%) 6261978461.64 ( -0.09%)
CoeffVar unixbench-dhry2reg-1 0.90 ( 0.00%) 0.98 ( -9.38%)
CoeffVar unixbench-dhry2reg-512 0.10 ( 0.00%) 0.17 ( -61.99%)
Max unixbench-dhry2reg-1 49758806.60 ( 0.00%) 49428847.90 ( -0.66%)
Max unixbench-dhry2reg-512 6273024869.70 ( 0.00%) 6273555460.00 ( 0.01%)
o NPS2
kernel: tip sis_short
Min unixbench-dhry2reg-1 48828251.70 ( 0.00%) 48591509.40 ( -0.48%)
Min unixbench-dhry2reg-512 6244987739.10 ( 0.00%) 6254966248.00 ( 0.16%)
Hmean unixbench-dhry2reg-1 48869882.65 ( 0.00%) 49230596.10 ( 0.74%)
Hmean unixbench-dhry2reg-512 6261073948.84 ( 0.00%) 6260685008.60 ( -0.01%)
CoeffVar unixbench-dhry2reg-1 0.08 ( 0.00%) 1.20 (-1347.66%)
CoeffVar unixbench-dhry2reg-512 0.23 ( 0.00%) 0.09 ( 59.12%)
Max unixbench-dhry2reg-1 48909163.40 ( 0.00%) 49752650.10 ( 1.72%)
Max unixbench-dhry2reg-512 6271411453.90 ( 0.00%) 6266517108.00 ( -0.08%)
o NPS4
kernel: tip sis_short
Min unixbench-dhry2reg-1 48523981.30 ( 0.00%) 48728886.20 ( 0.42%)
Min unixbench-dhry2reg-512 6253738837.10 ( 0.00%) 6260870171.70 ( 0.11%)
Hmean unixbench-dhry2reg-1 48781044.09 ( 0.00%) 48969711.29 ( 0.39%)
Hmean unixbench-dhry2reg-512 6264428474.90 ( 0.00%) 6277327761.28 ( 0.21%)
CoeffVar unixbench-dhry2reg-1 0.46 ( 0.00%) 0.43 ( 6.91%)
CoeffVar unixbench-dhry2reg-512 0.17 ( 0.00%) 0.29 ( -70.82%)
Max unixbench-dhry2reg-1 48925665.20 ( 0.00%) 49091708.50 ( 0.34%)
Max unixbench-dhry2reg-512 6274958506.80 ( 0.00%) 6296828879.20 ( 0.35%)
-> unixbench-syscall
o NPS1
kernel: tip sis_short
Min unixbench-syscall-1 2975654.80 ( 0.00%) 2971008.50 ( 0.16%)
Min unixbench-syscall-512 7840226.50 ( 0.00%) 6586485.10 ( 15.99%)
Amean unixbench-syscall-1 2976326.47 ( 0.00%) 2971920.50 * 0.15%*
Amean unixbench-syscall-512 7850493.90 ( 0.00%) 6597210.63 * 15.96%*
CoeffVar unixbench-syscall-1 0.03 ( 0.00%) 0.03 ( -14.26%)
CoeffVar unixbench-syscall-512 0.13 ( 0.00%) 0.27 (-103.14%)
Max unixbench-syscall-1 2977279.70 ( 0.00%) 2972935.80 ( 0.15%)
Max unixbench-syscall-512 7860838.90 ( 0.00%) 6617515.40 ( 15.82%)
o NPS2
kernel: tip sis_short
Min unixbench-syscall-1 2969863.60 ( 0.00%) 2974771.70 ( -0.17%)
Min unixbench-syscall-512 8053157.60 ( 0.00%) 7411223.90 ( 7.97%)
Amean unixbench-syscall-1 2970462.30 ( 0.00%) 2975278.63 * -0.16%*
Amean unixbench-syscall-512 8061454.50 ( 0.00%) 7437679.30 * 7.74%*
CoeffVar unixbench-syscall-1 0.02 ( 0.00%) 0.02 ( -17.72%)
CoeffVar unixbench-syscall-512 0.12 ( 0.00%) 0.34 (-179.38%)
Max unixbench-syscall-1 2970859.30 ( 0.00%) 2975972.90 ( -0.17%)
Max unixbench-syscall-512 8072312.30 ( 0.00%) 7461732.50 ( 7.56%)
o NPS4
kernel: tip sis_short
Min unixbench-syscall-1 2971799.80 ( 0.00%) 2974601.20 ( -0.09%)
Min unixbench-syscall-512 7824196.90 ( 0.00%) 8242480.10 ( -5.35%)
Amean unixbench-syscall-1 2973045.43 ( 0.00%) 2974739.93 * -0.06%*
Amean unixbench-syscall-512 7826302.17 ( 0.00%) 8261295.03 * -5.56%*
CoeffVar unixbench-syscall-1 0.04 ( 0.00%) 0.00 ( 86.39%)
CoeffVar unixbench-syscall-512 0.03 ( 0.00%) 0.37 (-1376.49%)
Max unixbench-syscall-1 2973786.50 ( 0.00%) 2974895.30 ( -0.04%)
Max unixbench-syscall-512 7828115.90 ( 0.00%) 8296830.40 ( -5.99%)
-> unixbench-pipe
o NPS1
kernel: tip sis_short
Min unixbench-pipe-1 2894765.30 ( 0.00%) 2904821.00 ( 0.35%)
Min unixbench-pipe-512 329818573.50 ( 0.00%) 329565756.00 ( -0.08%)
Hmean unixbench-pipe-1 2898803.38 ( 0.00%) 2911189.71 * 0.43%*
Hmean unixbench-pipe-512 330226401.69 ( 0.00%) 330389884.94 ( 0.05%)
CoeffVar unixbench-pipe-1 0.14 ( 0.00%) 0.22 ( -62.25%)
CoeffVar unixbench-pipe-512 0.11 ( 0.00%) 0.24 (-126.10%)
Max unixbench-pipe-1 2902691.20 ( 0.00%) 2917740.00 ( 0.52%)
Max unixbench-pipe-512 330440132.10 ( 0.00%) 331162497.90 ( 0.22%)
o NPS2
kernel: tip sis_short
Min unixbench-pipe-1 2895327.90 ( 0.00%) 2905421.90 ( 0.35%)
Min unixbench-pipe-512 328350065.60 ( 0.00%) 330137916.90 ( 0.54%)
Hmean unixbench-pipe-1 2899129.86 ( 0.00%) 2910562.69 * 0.39%*
Hmean unixbench-pipe-512 329436096.80 ( 0.00%) 330509036.17 ( 0.33%)
CoeffVar unixbench-pipe-1 0.12 ( 0.00%) 0.20 ( -70.84%)
CoeffVar unixbench-pipe-512 0.30 ( 0.00%) 0.10 ( 65.00%)
Max unixbench-pipe-1 2901619.40 ( 0.00%) 2916758.50 ( 0.52%)
Max unixbench-pipe-512 330239044.10 ( 0.00%) 330814020.50 ( 0.17%)
o NPS4
kernel: tip sis_short
Min unixbench-pipe-1 2901525.60 ( 0.00%) 2909864.00 ( 0.29%)
Min unixbench-pipe-512 330265873.90 ( 0.00%) 330543034.40 ( 0.08%)
Hmean unixbench-pipe-1 2906184.70 ( 0.00%) 2912725.52 * 0.23%*
Hmean unixbench-pipe-512 330854683.27 ( 0.00%) 331540275.79 ( 0.21%)
CoeffVar unixbench-pipe-1 0.14 ( 0.00%) 0.09 ( 39.44%)
CoeffVar unixbench-pipe-512 0.16 ( 0.00%) 0.27 ( -73.84%)
Max unixbench-pipe-1 2909154.50 ( 0.00%) 2914249.80 ( 0.18%)
Max unixbench-pipe-512 331245477.30 ( 0.00%) 332305755.00 ( 0.32%)
-> unixbench-spawn
o NPS1
kernel: tip sis_short
Min unixbench-spawn-1 6536.50 ( 0.00%) 6458.00 ( -1.20%)
Min unixbench-spawn-512 72571.40 ( 0.00%) 91525.90 ( 26.12%)
Hmean unixbench-spawn-1 6811.16 ( 0.00%) 6510.74 ( -4.41%)
Hmean unixbench-spawn-512 72801.77 ( 0.00%) 91829.95 * 26.14%*
CoeffVar unixbench-spawn-1 3.69 ( 0.00%) 1.00 ( 72.93%)
CoeffVar unixbench-spawn-512 0.27 ( 0.00%) 0.41 ( -50.84%)
Max unixbench-spawn-1 7021.00 ( 0.00%) 6583.60 ( -6.23%)
Max unixbench-spawn-512 72927.00 ( 0.00%) 92257.50 ( 26.51%)
o NPS2
kernel: tip sis_short
Min unixbench-spawn-1 7042.20 ( 0.00%) 7411.00 ( 5.24%)
Min unixbench-spawn-512 85571.60 ( 0.00%) 89549.50 ( 4.65%)
Hmean unixbench-spawn-1 7199.01 ( 0.00%) 7553.53 * 4.92%*
Hmean unixbench-spawn-512 85717.77 ( 0.00%) 89751.68 * 4.71%*
CoeffVar unixbench-spawn-1 3.50 ( 0.00%) 1.68 ( 51.98%)
CoeffVar unixbench-spawn-512 0.20 ( 0.00%) 0.28 ( -36.60%)
Max unixbench-spawn-1 7495.00 ( 0.00%) 7650.40 ( 2.07%)
Max unixbench-spawn-512 85909.20 ( 0.00%) 90028.30 ( 4.79%)
o NPS4
kernel: tip sis_short
Min unixbench-spawn-1 7521.90 ( 0.00%) 8404.10 ( 11.73%)
Min unixbench-spawn-512 84245.70 ( 0.00%) 91260.20 ( 8.33%)
Hmean unixbench-spawn-1 7659.12 ( 0.00%) 8526.01 * 11.32%*
Hmean unixbench-spawn-512 84908.77 ( 0.00%) 91365.07 * 7.60%*
CoeffVar unixbench-spawn-1 1.92 ( 0.00%) 2.06 ( -7.21%)
CoeffVar unixbench-spawn-512 0.76 ( 0.00%) 0.10 ( 86.60%)
Max unixbench-spawn-1 7815.40 ( 0.00%) 8729.60 ( 11.70%)
Max unixbench-spawn-512 85532.90 ( 0.00%) 91437.30 ( 6.90%)
-> unixbench-execl
o NPS1
kernel: tip sis_short
Min unixbench-execl-1 5421.50 ( 0.00%) 5466.40 ( 0.83%)
Min unixbench-execl-512 11213.50 ( 0.00%) 11720.30 ( 4.52%)
Hmean unixbench-execl-1 5443.75 ( 0.00%) 5468.53 ( 0.46%)
Hmean unixbench-execl-512 11311.94 ( 0.00%) 11809.97 * 4.40%*
CoeffVar unixbench-execl-1 0.38 ( 0.00%) 0.04 ( 89.57%)
CoeffVar unixbench-execl-512 1.03 ( 0.00%) 0.74 ( 27.60%)
Max unixbench-execl-1 5461.90 ( 0.00%) 5470.70 ( 0.16%)
Max unixbench-execl-512 11440.40 ( 0.00%) 11895.60 ( 3.98%)
o NPS2
kernel: tip sis_short
Min unixbench-execl-1 5089.10 ( 0.00%) 5119.50 ( 0.60%)
Min unixbench-execl-512 11772.70 ( 0.00%) 11591.40 ( -1.54%)
Hmean unixbench-execl-1 5321.65 ( 0.00%) 5251.49 ( -1.32%)
Hmean unixbench-execl-512 12201.73 ( 0.00%) 11665.67 ( -4.39%)
CoeffVar unixbench-execl-1 3.87 ( 0.00%) 2.33 ( 39.91%)
CoeffVar unixbench-execl-512 6.23 ( 0.00%) 1.04 ( 83.38%)
Max unixbench-execl-1 5453.90 ( 0.00%) 5359.00 ( -1.74%)
Max unixbench-execl-512 13111.60 ( 0.00%) 11805.80 ( -9.96%)
o NPS4
kernel: tip sis_short
Min unixbench-execl-1 5099.40 ( 0.00%) 5352.70 ( 4.97%)
Min unixbench-execl-512 11692.80 ( 0.00%) 13368.20 ( 14.33%)
Hmean unixbench-execl-1 5136.86 ( 0.00%) 5404.31 * 5.21%*
Hmean unixbench-execl-512 12053.71 ( 0.00%) 14018.53 * 16.30%*
CoeffVar unixbench-execl-1 1.05 ( 0.00%) 0.84 ( 20.12%)
CoeffVar unixbench-execl-512 3.85 ( 0.00%) 5.29 ( -37.45%)
Max unixbench-execl-1 5198.70 ( 0.00%) 5434.90 ( 4.54%)
Max unixbench-execl-512 12585.70 ( 0.00%) 14839.80 ( 17.91%)
On 10/23/2022 9:01 PM, Chen Yu wrote:
> At LPC 2022 Real-time and Scheduling Micro Conference we presented
> the cross CPU wakeup issue. This patch is a text version of the
> talk, and hopefully, we can clarify the problem and appreciate any
> feedback.
>
> The main purpose of this change is to avoid too many crosses CPU
> wake up when the system is busy. Please refer to the commit log
> of [PATCH 2/2] for detail.
>
> This patch set is composed of two parts. The first part is to introduce
> the definition of a short-duration task. The second part leverages the
> first part to choose a CPU where only one short-duration task is running
> on. This CPU is chosen as the candidate to place a woken task.
>
> This version is modified based on the following feedback on v1:
> 1. Tim suggested raising the bar to choose a CPU with a short-duration
> task, by checking if the short-duration task is the only runnable
> task on the target CPU.
> 2. To address Peter's concern: would this patch inhibit spreading the
> workload when there are idle CPUs around? The patch would only take
> effect when the system is relatively busy, and only choose the CPU
> where only one short-duration task is running.
> 3. Prateek, Honglwei and Hillf suggsted to prefer previous idle CPU to the
> CPU with short-duration task running.
>
> v1 link: https://lore.kernel.org/lkml/20220915165407.1776363-1-yu.c.chen@xxxxxxxxx/
>
> Chen Yu (2):
> sched/fair: Introduce short duration task check
> sched/fair: Choose the CPU where short task is running during wake up
>
> include/linux/sched.h | 8 ++++
> kernel/sched/core.c | 2 +
> kernel/sched/fair.c | 99 +++++++++++++++++++++++++++++++++++++++++
> kernel/sched/features.h | 1 +
> 4 files changed, 110 insertions(+)
>
Except for schbench with 128 workers in NPS4 mode, I do not
see any large regressions for the above workloads and I do
see small to moderate gains overall for most workload, even
the larger ones. I'll try to get data for more workload but
overall the idea seems promising. I'll also get some numbers
with the changes Peter suggested on Patch 1.
If there is any specific workload you would like me to run
on the test machine, please do let me know.
--
Thanks and Regards,
Prateek