On 7/23/20 11:20 PM, Rakesh Pillai wrote: > > >> -----Original Message----- >> From: Florian Fainelli <f.fainelli@xxxxxxxxx> >> Sent: Friday, July 24, 2020 12:33 AM >> To: Rakesh Pillai <pillair@xxxxxxxxxxxxxx>; 'Andrew Lunn' >> <andrew@xxxxxxx> >> Cc: ath10k@xxxxxxxxxxxxxxxxxxx; linux-wireless@xxxxxxxxxxxxxxx; linux- >> kernel@xxxxxxxxxxxxxxx; kvalo@xxxxxxxxxxxxxx; johannes@xxxxxxxxxxxxxxxx; >> davem@xxxxxxxxxxxxx; kuba@xxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; >> dianders@xxxxxxxxxxxx; evgreen@xxxxxxxxxxxx >> Subject: Re: [RFC 0/7] Add support to process rx packets in thread >> >> On 7/23/20 11:21 AM, Rakesh Pillai wrote: >>> >>> >>>> -----Original Message----- >>>> From: Florian Fainelli <f.fainelli@xxxxxxxxx> >>>> Sent: Tuesday, July 21, 2020 11:35 PM >>>> To: Andrew Lunn <andrew@xxxxxxx>; Rakesh Pillai >> <pillair@xxxxxxxxxxxxxx> >>>> Cc: ath10k@xxxxxxxxxxxxxxxxxxx; linux-wireless@xxxxxxxxxxxxxxx; linux- >>>> kernel@xxxxxxxxxxxxxxx; kvalo@xxxxxxxxxxxxxx; >> johannes@xxxxxxxxxxxxxxxx; >>>> davem@xxxxxxxxxxxxx; kuba@xxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; >>>> dianders@xxxxxxxxxxxx; evgreen@xxxxxxxxxxxx >>>> Subject: Re: [RFC 0/7] Add support to process rx packets in thread >>>> >>>> On 7/21/20 10:25 AM, Andrew Lunn wrote: >>>>> On Tue, Jul 21, 2020 at 10:44:19PM +0530, Rakesh Pillai wrote: >>>>>> NAPI gets scheduled on the CPU core which got the >>>>>> interrupt. The linux scheduler cannot move it to a >>>>>> different core, even if the CPU on which NAPI is running >>>>>> is heavily loaded. This can lead to degraded wifi >>>>>> performance when running traffic at peak data rates. >>>>>> >>>>>> A thread on the other hand can be moved to different >>>>>> CPU cores, if the one on which its running is heavily >>>>>> loaded. During high incoming data traffic, this gives >>>>>> better performance, since the thread can be moved to a >>>>>> less loaded or sometimes even a more powerful CPU core >>>>>> to account for the required CPU performance in order >>>>>> to process the incoming packets. >>>>>> >>>>>> This patch series adds the support to use a high priority >>>>>> thread to process the incoming packets, as opposed to >>>>>> everything being done in NAPI context. >>>>> >>>>> I don't see why this problem is limited to the ath10k driver. I expect >>>>> it applies to all drivers using NAPI. So shouldn't you be solving this >>>>> in the NAPI core? Allow a driver to request the NAPI core uses a >>>>> thread? >>>> >>>> What's more, you should be able to configure interrupt affinity to steer >>>> RX processing onto a desired CPU core, is not that working for you >>>> somehow? >>> >>> Hi Florian, >>> Yes, the affinity of IRQ does work for me. >>> But the affinity of IRQ does not happen runtime based on load. >> >> It can if you also run irqbalance. > > > Hi Florian, > > Is it some kernel feature ? Sorry I am not aware of this ? > I know it can be done in userspace. The kernel interface is /proc/<irq>/smp_affinity and the users-space implementation resides here: https://github.com/Irqbalance/irqbalance -- Florian
