ath10k: implement NAPI support

Add NAPI support for rx and tx completion. NAPI poll is scheduled
from interrupt handler. The design is as below

 - on interrupt
     - schedule napi and mask interrupts
 - on poll
   - process all pipes (no actual Tx/Rx)
   - process Rx within budget
   - if quota exceeds budget reschedule napi poll by returning budget
   - process Tx completions and update budget if necessary
   - process Tx fetch indications (pull-push)
   - push any other pending Tx (if possible)
   - before resched or napi completion replenish htt rx ring buffer
   - if work done < budget, complete napi poll and unmask interrupts

This change also get rid of two tasklets (intr_tq and txrx_compl_task).

Measured peak throughput with NAPI on IPQ4019 platform in controlled
environment. No noticeable reduction in throughput is seen and also
observed improvements in CPU usage. Approx. 15% CPU usage got reduced
in UDP uplink case.

DL: AP DUT Tx
UL: AP DUT Rx

IPQ4019 (avg. cpu usage %)

========
                TOT              +NAPI
              ===========      =============
TCP DL       644 Mbps (42%)    645 Mbps (36%)
TCP UL       673 Mbps (30%)    675 Mbps (26%)
UDP DL       682 Mbps (49%)    680 Mbps (49%)
UDP UL       720 Mbps (28%)    717 Mbps (11%)

Signed-off-by: Rajkumar Manoharan <rmanohar@qti.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
This commit is contained in:
Rajkumar Manoharan 2016-09-02 19:46:09 +03:00 committed by Kalle Valo
parent c39265f72a
commit 3c97f5de1f
8 changed files with 159 additions and 96 deletions

View file

@ -1665,7 +1665,6 @@ struct ath10k_htt {
/* This is used to group tx/rx completions separately and process them
* in batches to reduce cache stalls */
struct tasklet_struct txrx_compl_task;
struct sk_buff_head rx_compl_q;
struct sk_buff_head rx_in_ord_compl_q;
struct sk_buff_head tx_fetch_ind_q;
@ -1798,5 +1797,6 @@ int ath10k_htt_tx(struct ath10k_htt *htt,
struct sk_buff *msdu);
void ath10k_htt_rx_pktlog_completion_handler(struct ath10k *ar,
struct sk_buff *skb);
int ath10k_htt_txrx_compl_task(struct ath10k *ar, int budget);
#endif