Re: [PATCH v2 2/2] sched/numa: Apply remote socket distance averaging for Hygon CPUs
Guo Chaohong <[email protected]>
| Newsgroups | gmane.linux.kernel |
|---|---|
| Message-ID | <[email protected]> |
On 8/6/2026 11:15 AM, Zhan Xusheng wrote:
> On Thu, Aug 06, 2026 at 08:35:09AM +0800, Chaohong Guo wrote:
>> For better performace, we do the same as Intel is doing on intel GNR/CWF.
>> That reduces sched domains to 4-level NUMA and eliminates cross-socket
>> sched groups in each domain:
>
> The refactor of arch_sched_node_distance() looks functionally equivalent
> for the existing Intel cases: hoisting the topology_max_packages() == 1
> early return, and turning the "return d / return slit_cluster_distance()"
> branches into "d = slit_cluster_distance() when
> topology_num_nodes_per_package() >= 3", yields the same result for
> GRANITERAPIDS_X / ATOM_DARKMONT_X. So no change there, good.
>
> One thing I couldn't tell from the changelog: the referenced commit
> 4d6dd05d07d0 is titled "sched/topology: Fix sched domain build error for
> GNR, CWF in SNC-3 mode" -- i.e. on Intel the asymmetric SNC-3 distances
> made the sched-domain build actually fail. This patch is instead framed
> as a load-balancing improvement ("For better performace", "suboptimal
> remote-socket CPU selection"), and the diagram shows domains that do
> build (levels 1-7 listed).
>
> So: does the Hygon NPS-6 case also hit a sched-domain build error/warning
> (a functional fix, like the Intel one), or is it purely a
> load-balancing/performance change? If it is the latter, would you be able
> to include benchmark numbers showing the improvement? For a change to the
> NUMA distance function / domain shape that seems worth having, and it
> would also make clear how this differs from the Intel build-error fix it
> is modeled on.
We benchmarked MySQL, ClickHouse, and other representative workloads. The results showed performance improvements
in all tested cases, with gains ranging from 5% .
clickbench/clickhouse :
192 Base 10 rounds SNC3+No overlap 150 rounds Base SNC3+No overlap Base SNC3+No overlap $
query cold_run | hot_run1 | hot_run2 $
1 0.0016 0.0014 12.50% | 0.0013 0.00102 21.54% | 0.001 0.001 0.00%$
2 0.0836 0.07196 13.92% | 0.0153 0.01768 -15.56% | 0.0156 0.015413333 1.20%$
3 0.1444 0.140353333 2.80% | 0.0148 0.014073333 4.91% | 0.0147 0.014246667 3.08%$
4 0.4151 0.414906667 0.05% | 0.0176 0.015366667 12.69% | 0.0168 0.015206667 9.48%$
5 0.5444 0.54358 0.15% | 0.1422 0.140606667 1.12% | 0.1447 0.140953333 2.59%$
6 0.7963 0.795386667 0.11% | 0.1515 0.148833333 1.76% | 0.1489 0.148693333 0.14%$
7 0.0046 0.004226667 8.12% | 0.0038 0.003946667 -3.86% | 0.0037 0.003866667 -4.50%$
8 0.0264 0.023386667 11.41% | 0.0216 0.019186667 11.17% | 0.0214 0.019746667 7.73%$
9 0.6561 0.653253333 0.43% | 0.1196 0.11574 3.23% | 0.117 0.114386667 2.23%$
10 0.7967 0.79246 0.53% | 0.1256 0.123653333 1.55% | 0.1247 0.1222 2.00%$
11 0.47 0.46812 0.40% | 0.0687 0.065393333 4.81% | 0.0691 0.066226667 4.16%$
12 0.4955 0.493753333 0.35% | 0.0792 0.075866667 4.21% | 0.0799 0.077406667 3.12%$
13 0.812 0.802613333 1.16% | 0.1564 0.154686667 1.10% | 0.1511 0.15128 -0.12%$
14 1.2099 1.198433333 0.95% | 0.1807 0.178466667 1.24% | 0.1808 0.180213333 0.32%$
15 0.8717 0.857206667 1.66% | 0.1547 0.142033333 8.19% | 0.1618 0.143266667 11.45%$
16 0.4823 0.47796 0.90% | 0.0889 0.086666667 2.51% | 0.0872 0.085966667 1.41%$
17 1.2846 1.270586667 1.09% | 0.2575 0.262233333 -1.84% | 0.2615 0.27116 -3.69%$
18 1.2369 1.240953333 -0.33% | 0.2411 0.215066667 10.80% | 0.2262 0.211033333 6.70%$
19 2.046 2.05788 -0.58% | 0.4103 0.421406667 -2.71% | 0.4662 0.426066667 8.61%$
20 0.1586 0.158846667 -0.16% | 0.0024 0.00254 -5.83% | 0.0021 0.002 4.76%$
21 4.8204 4.81756 0.06% | 0.0222 0.02148 3.24% | 0.0202 0.020206667 -0.03%$
22 4.8637 4.85928 0.09% | 0.0161 0.014966667 7.04% | 0.0133 0.01314 1.20%$
23 10.1773 10.03627333 1.39% | 0.5177 0.429133333 17.11% | 0.5251 0.454086667 13.52%$
24 0.3491 0.340746667 2.39% | 0.0539 0.050406667 6.48% | 0.0489 0.04618 5.56%$
25 0.8278 0.8248 0.36% | 0.054 .053033333 1.79% | 0.0403 0.0382 5.21%$
26 0.7047 0.7044 0.04% | 0.0459 0.04642 -1.13% | 0.0436 0.045266667 -3.82%$
27 0.8263 0.827233333 -0.11% | 0.0518 0.05786 -11.70% | 0.0394 0.038213333 3.01%$
28 0.4877 0.486706667 0.20% | 0.0408 0.040753333 0.11% | 0.0408 0.041086667 -0.70%$
29 4.2963 4.242473333 1.25% | 0.2718 0.256586667 5.60% | 0.2612 0.252573333 3.30%$
30 0.1704 0.170693333 -0.17% | 0.0661 0.065826667 0.41% | 0.066 0.065826667 0.26%$
31 0.6178 0.61514 0.43% | 0.095 .091386667 3.80% | 0.0959 0.088826667 7.38%$
32 2.0294 2.024113333 0.26% | 0.1525 0.123653333 18.92% | 0.1508 0.11932 20.88%$
33 2.2297 2.21918 0.47% | 0.5283 0.451426667 14.55% | 0.572 0.441673333 22.78%$
34 5.156 5.056313333 1.93% | 0.8417 0.470013333 44.16% | 0.9473 0.4826 49.06%$
35 5.1236 5.05868 1.27% | 0.7324 0.456533333 37.67% | 0.7682 0.466333333 39.30%$
36 0.3046 0.295393333 3.02% | 0.0714 0.064266667 9.99% | 0.0679 0.062433333 8.05%$
37 0.0744 0.073853333 0.73% | 0.0398 0.0392 1.51% | 0.0397 0.03976 -0.15%$
38 0.039 0.03868 0.82% | 0.0265 0.025726667 2.92% | 0.0257 0.025273333 1.66%$
39 0.0595 0.0592 0.50% | 0.0183 0.018686667 -2.11% | 0.0195 0.018413333 5.57%$
40 0.1307 0.128733333 1.50% | 0.0762 0.074006667 2.88% | 0.0761 0.075753333 0.46%$
41 0.0175 0.0178 -1.71% | 0.0123 0.01284 -4.39% | 0.0128 0.0128 0.00%$
42 0.0174 0.017753333 -2.03% | 0.0135 0.01318 2.37% | 0.0132 0.013513333 -2.37%$
43 0.0081 0.008226667 -1.56% | 0.0119 0.012333333 -3.64% | 0.0123 0.01282 -4.23%$
>
> Minor, on 1/2: HYGON_F18_M04 and HYGON_F18_M06 are added but only
> HYGON_F18_M07 has a user in this series. Are the other two intended as a
> reference for the new header, or could they be added when a user shows up?
>
We plan to refactor Hygon CPU related code (e.g., node management, EDAC, etc.) and upstream more Hygon support in the
future. Since some of these changes currently define macros in private files, we prefer to consolidate them into a
common header to improve maintainability.
thanks,
-chaohong> Thanks,
> Zhan Xusheng