ath10k performance, master branch from 20160407

[Roman Yeryomin]

Rajkumar,

I took backports from
git://git.kernel.org/pub/scm/linux/kernel/git/backports/backports.git,
took latest ath tree from
git://git.kernel.org/pub/scm/linux/kernel/git/kvalo/ath.git, generated
backports-output based on ath master branch, refreshed openwrt
patches.
And saw big performance degradation. Am I doing something wrong?

Regards,
Roman

On 8 April 2016 at 18:34, Manoharan, Rajkumar <rmanohar at qti.qualcomm.com> wrote:
> Roman,
>
> Which backports version are you using? I don't see codel changes in ath.git/wireless-drivers.git.
> Hope you are using same firmware.
>
> -Rajkumar
> ________________________________________
> From: ath10k <ath10k-bounces at lists.infradead.org> on behalf of Roman Yeryomin <leroi.lists at gmail.com>
> Sent: Friday, April 8, 2016 8:14 PM
> To: ath10k at lists.infradead.org
> Subject: ath10k performance, master branch from 20160407
>
> Hello!
>
> I've seen performance patches were commited so I've decided to give it
> a try (using 4.1 kernel and backports).
> The results are quite disappointing: TCP download (client pov) dropped
> from 750Mbps to ~550 and UDP shows completely weird behavour - if
> generating 900Mbps it gives 30Mbps max, if generating 300Mbps it gives
> 250Mbps, before (latest official backports release from January) I was
> able to get 900Mbps.
> Hardware is basically ap152 + qca988x 3x3.
> When running perf top I see that fq_codel_drop eats a lot of cpu.
> Here is the output when running iperf3 UDP test:
>
>     45.78%  [kernel]       [k] fq_codel_drop
>      3.05%  [kernel]       [k] ag71xx_poll
>      2.18%  [kernel]       [k] skb_release_data
>      2.01%  [kernel]       [k] r4k_dma_cache_inv
>      1.73%  [kernel]       [k] eth_type_trans
>      1.24%  [kernel]       [k] build_skb
>      1.20%  [mac80211]     [k] ieee80211_tx_dequeue
>      1.03%  [kernel]       [k] __delay
>      0.98%  [kernel]       [k] fq_codel_enqueue
>      0.94%  [kernel]       [k] __netif_receive_skb_core
>      0.93%  [kernel]       [k] skb_release_head_state
>      0.88%  [ath10k_core]  [k] ath10k_htt_tx
>      0.87%  [kernel]       [k] __dev_queue_xmit
>      0.84%  [mac80211]     [k] ieee80211_tx_status
>      0.81%  [kernel]       [k] __build_skb
>      0.80%  [mac80211]     [k] __ieee80211_subif_start_xmit
>      0.77%  [kernel]       [k] br_handle_frame_finish
>      0.75%  [kernel]       [k] __qdisc_run
>      0.73%  [kernel]       [k] skb_recycler_consume
>      0.72%  [kernel]       [k] kfree_skb
>      0.72%  [kernel]       [k] get_page_from_freelist
>      0.69%  [kernel]       [k] br_fdb_update
>      0.69%  [kernel]       [k] br_handle_frame
>      0.67%  [kernel]       [k] __copy_user_common
>      0.66%  [kernel]       [k] __skb_flow_dissect
>      0.65%  [ath10k_core]  [k] ath10k_txrx_tx_unref
>      0.60%  [kernel]       [k] kmem_cache_alloc
>      0.60%  [mac80211]     [k] sta_addr_hash
>      0.56%  [kernel]       [k] fq_codel_dequeue
>      0.53%  [kernel]       [k] __local_bh_enable_ip
>      0.50%  [kernel]       [k] __br_fdb_get
>
> What could be the reason?
> I've seen there are some patches from Michal which touch fq_codel,
> would those help or not?
>
>
> Regards,
> Roman
>
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