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/[email protected]/
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(+)
--
2.25.1
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/[email protected]/
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/[email protected]/
>
> 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
On 2022-11-22 at 16:01:42 +0530, K Prateek Nayak wrote:
> Hello Chenyu,
>
> I've tested v2 series on an dual socket Zen3 system (2 x 64C/128T) and
> the results are largely positive.
>
Thank you Prateek, and sorry for late response.
> 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/[email protected]/
> 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.
This reminds me that, previously I tested with Cstates > C1 disabled, and
with turbo disabled, so as to mitigate possible deviation. May I know if
all C-states and turbo are enabled in your test besides tbench?
>
> ~~~~~~~~~~
> ~ 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%)
>
>
> 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.
I spent sometime to dig into the issue which motivates me to propose this
solution. And it was found that this issue could not be easily solved
directly because there seems to be an inevitable race condition window, with the
increasing of CPU number, this race condition is exposed easlier. So
current patch is an indirect solution to avoid that, I'll send the detail
in v3.
>
> If there is any specific workload you would like me to run
> on the test machine, please do let me know.
Thanks for always helping us to test the patch, I'll send v3 once I get the
result and we can discuss on that then.
thanks,
Chenyu
Hello Chenyu,
On 11/30/2022 9:33 AM, Chen Yu wrote:
> On 2022-11-22 at 16:01:42 +0530, K Prateek Nayak wrote:
>> Hello Chenyu,
>>
>> I've tested v2 series on an dual socket Zen3 system (2 x 64C/128T) and
>> the results are largely positive.
>>
> Thank you Prateek, and sorry for late response.
Thank you for taking a look at the report.
>> 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:
>>
>> [..snip..]
>>
>> 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/[email protected]/
>> 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.
> This reminds me that, previously I tested with Cstates > C1 disabled, and
> with turbo disabled, so as to mitigate possible deviation. May I know if
> all C-states and turbo are enabled in your test besides tbench?
I do run with all C-states and turbo enabled with performance governor.
I can do a parallel run with C2 and turbo disabled to bring down any
possibility of external factors affecting the results. In the past,
we've seen some issues come to light when running with C2 and turbo
enabled so I had stuck to it. Thank you for pointing this out.
>>
>> [..snip..]
>>
>> 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.
> I spent sometime to dig into the issue which motivates me to propose this
> solution. And it was found that this issue could not be easily solved
> directly because there seems to be an inevitable race condition window, with the
> increasing of CPU number, this race condition is exposed easlier. So
> current patch is an indirect solution to avoid that, I'll send the detail
> in v3.
I see that v3 is out. Thank you for the detailed explanation and the
visualization of the bottleneck in v3 Patch 2.
>>
>> If there is any specific workload you would like me to run
>> on the test machine, please do let me know.
> Thanks for always helping us to test the patch, I'll send v3 once I get the
> result and we can discuss on that then.
I've queued up runs for v3 with the same set of benchmarks reported
above. I will make a point to include results with C2 and turbo disabled
to reduce external variables.
I'll share the results on v3 in the coming week.
--
Thanks and Regards,
Prateek