[RFC v2 05/10] ath10k: htt: High latency TX support

Erik Stromdahl erik.stromdahl at gmail.com
Sat Jun 17 10:59:59 PDT 2017

On 2017-06-13 19:38, Peter Oh wrote:
> On 06/12/2017 08:03 AM, Erik Stromdahl wrote:
>> Add HTT TX function for HL interfaces.
>> Intended for SDIO and USB.
>> Signed-off-by: Erik Stromdahl <erik.stromdahl at gmail.com>
>> ---
>> diff --git a/drivers/net/wireless/ath/ath10k/mac.c b/drivers/net/wireless/ath/ath10k/mac.c
>> index 48418f9..c5fd803 100644
>> --- a/drivers/net/wireless/ath/ath10k/mac.c
>> +++ b/drivers/net/wireless/ath/ath10k/mac.c
>> @@ -3572,7 +3572,10 @@ static int ath10k_mac_tx_submit(struct ath10k *ar,
>>       switch (txpath) {
>>       case ATH10K_MAC_TX_HTT:
>> -        ret = ath10k_htt_tx(htt, txmode, skb);
>> +        if (ar->is_high_latency)
> Can we use function pointers at initial time to avoid condition check at hot path?
> I'm afraid adding more lines on hot path.
I haven't made any comparison of assembly code between if-paths or function pointers,
but since most architectures have conditional instructions I don't think the
penalty is that big (if there is any penalty at all).
There are plenty of other condition checks in the RX path (mac80211 is full of them),
so I don't really see this as an issue.
That being said, any improvement is always welcome (even micro optimizations
if they are beneficial).
I will think about this and see if adding function pointers can be done in a nice way.

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