hnyman
May 7, 2020, 6:39pm
2382
Not much difference, I think.
And generally, the new kernels have actually caused performance degradation, as new functionality and complexity is usually being added. E.g. kernel 4.4 a few years ago was much slower than 4.1 for many routers...
The likely result is a Linux kernel update. One of the updates from 3.18 to 4.1 to 4.4 to 4.9 to 4.14.
Example: routing performance deteriorated in a major way between AA12.09 and BB14.07 as the routing cache was remove from Linux kernel in kernel 3.6, so the performance of AA12.09 with kernel 3.3 and of BB14.07 with 3.10 differed quite much. Same has happened with other major kernel version jumps, so finding the Openwrt commit may not help that much, if the commit is a major kernel version up…
e.g. by introducing new sporadic race conditions that affect just certain hardware combinations and use cases. Linux kernel development is not specifically tailored toward router usage.
One example is that HTB qdisc performance deteriorated between kernel 4.4 and 4.8 in a way that affect dual-core devices like 8065 in R7800. Discussion about that can be found in SQM bug discussion:
https://github.com/tohojo/sqm-scripts/issues/48#issuecomment-260991014
Kernel devs had noticed that problem and…
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