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Message-ID: <dcc14883-51c9-c1bb-bbea-1b309eccedf2@quicinc.com>
Date:   Fri, 2 Sep 2022 18:47:41 +0530
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Subject: Re: [PATCH 1/3] ath11k: Enable threaded NAPI on WCN6750
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To:     Kalle Valo <kvalo@kernel.org>
CC:     <ath11k@lists.infradead.org>, <linux-wireless@vger.kernel.org>
References: <20220720135113.15755-1-quic_mpubbise@quicinc.com>
 <20220720135113.15755-2-quic_mpubbise@quicinc.com>
 <87czceaqng.fsf@kernel.org>
From:   Manikanta Pubbisetty <quic_mpubbise@quicinc.com>
In-Reply-To: <87czceaqng.fsf@kernel.org>
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On 9/2/2022 6:18 PM, Kalle Valo wrote:
> Manikanta Pubbisetty <quic_mpubbise@quicinc.com> writes:
> 
>> Enable threaded NAPI on WCN6750. Unlike traditional NAPI poll which
>> runs in softirq context and on the core which scheduled the NAPI,
>> threaded NAPI makes use of kernel threads which are under direct
>> control of the scheduler and helps in balancing the NAPI processing
>> load across multiple CPUs thereby improving throughput.
>>
>> In the case of WCN6750, enabling threaded NAPI has improved
>> 160 MHz RX throughput by nearly 400 Mbps. This should give similar
>> gains for other ath11k devices as well, therefore enable threaded
>> NAPI on all other devices.
>>
>> Tested-on: WCN6750 hw1.0 AHB WLAN.MSL.1.0.1-00887-QCAMSLSWPLZ-1
>>
>> Signed-off-by: Manikanta Pubbisetty <quic_mpubbise@quicinc.com>
>> ---
>>   drivers/net/wireless/ath/ath11k/ahb.c  | 1 +
>>   drivers/net/wireless/ath/ath11k/pcic.c | 1 +
>>   2 files changed, 2 insertions(+)
>>
>> diff --git a/drivers/net/wireless/ath/ath11k/ahb.c b/drivers/net/wireless/ath/ath11k/ahb.c
>> index d7d33d5cdfc5..e44e2f29a88f 100644
>> --- a/drivers/net/wireless/ath/ath11k/ahb.c
>> +++ b/drivers/net/wireless/ath/ath11k/ahb.c
>> @@ -314,6 +314,7 @@ static void ath11k_ahb_ext_irq_enable(struct ath11k_base *ab)
>>   		struct ath11k_ext_irq_grp *irq_grp = &ab->ext_irq_grp[i];
>>   
>>   		if (!irq_grp->napi_enabled) {
>> +			dev_set_threaded(&irq_grp->napi_ndev, true);
>>   			napi_enable(&irq_grp->napi);
>>   			irq_grp->napi_enabled = true;
>>   		}
>> diff --git a/drivers/net/wireless/ath/ath11k/pcic.c b/drivers/net/wireless/ath/ath11k/pcic.c
>> index cf12b98c480d..c703db19de51 100644
>> --- a/drivers/net/wireless/ath/ath11k/pcic.c
>> +++ b/drivers/net/wireless/ath/ath11k/pcic.c
>> @@ -440,6 +440,7 @@ void ath11k_pcic_ext_irq_enable(struct ath11k_base *ab)
>>   		struct ath11k_ext_irq_grp *irq_grp = &ab->ext_irq_grp[i];
>>   
>>   		if (!irq_grp->napi_enabled) {
>> +			dev_set_threaded(&irq_grp->napi_ndev, true);
>>   			napi_enable(&irq_grp->napi);
>>   			irq_grp->napi_enabled = true;
>>   		}
> 
> The commit log claims that this enabled _only_ on WCN6750 but aren't we
> enabling it on all ath11k hardware, or am I missing something? I admit I
> didn't check this very carefully.
> 
> (reads the commit log one more time)
> 
> Ah, in the last sentence you mention that it's enabled on all hardware.
> That's quite easy to miss and the commit log is quite misleading, please
> emphasise already in the title and the first sentence that this is for
> all hardware.

My Bad, yes you right. The patch was made initially only for WCN6750 and
was enabled later for all devices.

> 
> Also more testing would be nice. Enabling something like this with
> testing only on one hardware family (WCN7850) can be risky. I always get
> warm fuzzy feelings if a patch is tested with all three hardware
> families we currently support:
> 
> * IPQ8074 etc
> * QCA6390 etc
> * WCN7850
> 

WCN7850 should be an ath12k device If I'm correct.

Regardless of the chip family, even I feel that the tput changes like 
these should be tested on all the chipsets. Availability of the hardware 
and time are something which are stopping me in testing the changes on 
all supported targets.

As I said, I had made the changes only to WCN6750 initially (using a 
hw_param). Can we take that approach for now and enable this for other 
targets only if required & upon thorough testing?

Thanks,
Manikanta