[Make-wifi-fast] [PATCH] ath10k: snoc: enable threaded napi on WCN3990
Bob McMahon
bob.mcmahon at broadcom.com
Thu Dec 29 00:54:15 EST 2022
A bit of a tangent but iperf 2's enhanced option provides sampled RTT and
CWND in the interval output. I requires -e. It also provide the connect
time, the icwnd, irtt and the mss per the connect.
[rjmcmahon at rjm-nas ~]$ iperf -c 192.168.1.85 -i 1 -e
------------------------------------------------------------
Client connecting to 192.168.1.85, TCP port 5001 with pid 20041 (1 flows)
Write buffer size: 131072 Byte
TOS set to 0x0 (Nagle on)
TCP window size: 16.0 KByte (default)
------------------------------------------------------------
[ 1] local 192.168.1.73%eno1 port 38822 connected with 192.168.1.85 port
5001 (sock=3) (icwnd/mss/irtt=14/1448/246) (ct=0.32 ms) on 2022-12-28
21:51:13 (PST)
[ ID] Interval Transfer Bandwidth Write/Err Rtry
Cwnd/RTT(var) NetPwr
[ 1] 0.00-1.00 sec 114 MBytes 952 Mbits/sec 908/0 3
353K/1901(59) us 62606
[ 1] 1.00-2.00 sec 111 MBytes 932 Mbits/sec 889/0 0
354K/2029(115) us 57429
[ 1] 2.00-3.00 sec 112 MBytes 937 Mbits/sec 894/0 3
354K/2061(84) us 56855
[ 1] 3.00-4.00 sec 112 MBytes 938 Mbits/sec 895/0 3
354K/2027(115) us 57873
[ 1] 4.00-5.00 sec 112 MBytes 938 Mbits/sec 895/0 6
354K/2046(68) us 57336
[ 1] 5.00-6.00 sec 112 MBytes 937 Mbits/sec 894/0 0
374K/2160(109) us 54249
[ 1] 6.00-7.00 sec 111 MBytes 933 Mbits/sec 890/0 2
374K/2155(115) us 54132
[ 1] 7.00-8.00 sec 111 MBytes 934 Mbits/sec 891/0 2
374K/2139(120) us 54598
[ 1] 8.00-9.00 sec 112 MBytes 938 Mbits/sec 895/0 0
374K/2129(126) us 55101
[ 1] 9.00-10.00 sec 112 MBytes 935 Mbits/sec 892/0 1
374K/2200(102) us 53144
[ 1] 0.00-10.03 sec 1.09 GBytes 935 Mbits/sec 8944/0 20
374K/4082(4010) us 28632
Bob
On Wed, Dec 28, 2022 at 4:49 PM Dave Taht via Make-wifi-fast <
make-wifi-fast at lists.bufferbloat.net> wrote:
> On Wed, Dec 28, 2022 at 3:53 PM Abhishek Kumar <kuabhs at chromium.org>
> wrote:
> >
> > Apologies for the late reply, Thanks Dave for your comment. My answer is
> inline.
> >
> > On Tue, Dec 20, 2022 at 7:10 AM Dave Taht <dave.taht at gmail.com> wrote:
> > >
> > > I am always interested in flent.org tcp_nup, tcp_ndown, and rrul_be
> > > tests on wifi hardware. In AP mode, especially, against a few clients
> > > in rtt_fair on the "ending the anomaly" test suite at the bottom of
> > > this link: https://www.cs.kau.se/tohojo/airtime-fairness/ . Of these,
> > > it's trying to optimize bandwidth more fairly and keep latencies low
> > > when 4 or more stations are trying to transmit (in a world with 16 or
> > > more stations online), that increasingly bothers me the most. I'm
> > > seeing 5+ seconds on some rtt_fair-like tests nowadays.
> > I used testing using iperf and conductive setup and fetched the
> > throughput data(mentioned below).
> > >
> > > I was also seeing huge simultaneous upload vs download disparities on
> > > the latest kernels, on various threads over here:
> > > https://forum.openwrt.org/t/aql-and-the-ath10k-is-lovely/59002 and
> > > more recently here:
> > >
> https://forum.openwrt.org/t/reducing-multiplexing-latencies-still-further-in-wifi/133605
> > Interesting, thanks for the pointer and probably the Qualcomm team is
> > aware of it.
> > >
> > > I don't understand why napi with the default budget (64) is even
> > > needed on the ath10k, as a single txop takes a minimum of ~200us, but
> > > perhaps your patch will help. Still, measuring the TCP statistics
> > > in-band would be nice to see. Some new tools are appearing that can do
> > > this, Apple's goresponsiveness, crusader... that are simpler to use
> > > than flent.
> > Here are some of the additional raw data with and without threaded napi:
> > ==================================================
> > udp_rx(Without threaded NAPI)
> > 435.98+-5.16 : Channel 44
> > 439.06+-0.66 : Channel 157
> >
> > udp_rx(With threaded NAPI)
> > 509.73+-41.03 : Channel 44
> > 549.97+-7.62 : Channel 157
> > ===================================================
> > udp_tx(Without threaded NAPI)
> > 461.31+-0.69 : Channel 44
> > 461.46+-0.78 : Channel 157
> >
> > udp_tx(With threaded NAPI)
> > 459.20+-0.77 : Channel 44
> > 459.78+-1.08 : Channel 157
> > ===================================================
> > tcp_rx(Without threaded NAPI)
> > 472.63+-2.35 : Channel 44
> > 469.29+-6.31 : Channel 157
> >
> > tcp_rx(With threaded NAPI)
> > 498.49+-2.44 : Channel 44
> > 541.14+-40.65 : Channel 157
> > ===================================================
> > tcp_tx(Without threaded NAPI)
> > 317.34+-2.37 : Channel 44
> > 317.01+-2.56 : Channel 157
> >
> > tcp_tx(With threaded NAPI)
> > 371.34+-2.36 : Channel 44
> > 376.95+-9.40 : Channel 157
>
> My concern is primarily with the induced tcp latency on this test. A
> way to check that is to run wireshark on your test client driving the
> test, capture the iperf traffic, and then plot the "Statistics->TCP
> stream statistics for both throughput and rtt. Would it be possible
> for you to do that and put up those plots somewhere?
>
> The worst case test is a tcp bidirectional test which I don't know if
> older iperfs can do. (iperf2 has new bounceback and bidir tests)
>
> Ideally stuff going in either direction, would not look as horrible,
> as it did, back in 2016, documented in this linuxplumbers presentation
> here:
> https://blog.linuxplumbersconf.org/2016/ocw/system/presentations/3963/original/linuxplumbers_wifi_latency-3Nov.pdf
> and discussed on lwn, here: https://lwn.net/Articles/705884/
>
> I worry about folk achieving slightly better tcp throughput at the
> expense of clobbering in-tcp-stream latency. Back then we were
> shooting for no more than 40ms extra latency under load on this chip,
> down from (unusable) seconds. Presently elsewhere, on other chips,
> we're getting 8ms with stuff that's not in tree for the ath10k, there
> is a slight cost in single stream throughput but when multiple streams
> are in use, on multiple stations, things like web pages fly,
> irrespective of load.
>
>
> > ====================================================
> >
> > >
> > > On Tue, Dec 20, 2022 at 12:17 AM Abhishek Kumar <kuabhs at chromium.org>
> wrote:
> > > >
> > > > NAPI poll can be done in threaded context along with soft irq
> > > > context. Threaded context can be scheduled efficiently, thus
> > > > creating less of bottleneck during Rx processing. This patch is
> > > > to enable threaded NAPI on ath10k driver.
> > > >
> > > > Based on testing, it was observed that on WCN3990, the CPU0 reaches
> > > > 100% utilization when napi runs in softirq context. At the same
> > > > time the other CPUs are at low consumption percentage. This
> > > > does not allow device to reach its maximum throughput potential.
> > > > After enabling threaded napi, CPU load is balanced across all CPUs
> > > > and following improvments were observed:
> > > > - UDP_RX increase by ~22-25%
> > > > - TCP_RX increase by ~15%
> > > >
> > > > Tested-on: WCN3990 hw1.0 SNOC WLAN.HL.3.2.2-00696-QCAHLSWMTPL-1
> > > > Signed-off-by: Abhishek Kumar <kuabhs at chromium.org>
> > > > ---
> > > >
> > > > drivers/net/wireless/ath/ath10k/core.c | 16 ++++++++++++++++
> > > > drivers/net/wireless/ath/ath10k/hw.h | 2 ++
> > > > drivers/net/wireless/ath/ath10k/snoc.c | 3 +++
> > > > 3 files changed, 21 insertions(+)
> > > >
> > > > diff --git a/drivers/net/wireless/ath/ath10k/core.c
> b/drivers/net/wireless/ath/ath10k/core.c
> > > > index 5eb131ab916fd..ee4b6ba508c81 100644
> > > > --- a/drivers/net/wireless/ath/ath10k/core.c
> > > > +++ b/drivers/net/wireless/ath/ath10k/core.c
> > > > @@ -100,6 +100,7 @@ static const struct ath10k_hw_params
> ath10k_hw_params_list[] = {
> > > > .hw_restart_disconnect = false,
> > > > .use_fw_tx_credits = true,
> > > > .delay_unmap_buffer = false,
> > > > + .enable_threaded_napi = false,
> > > > },
> > > > {
> > > > .id = QCA988X_HW_2_0_VERSION,
> > > > @@ -140,6 +141,7 @@ static const struct ath10k_hw_params
> ath10k_hw_params_list[] = {
> > > > .hw_restart_disconnect = false,
> > > > .use_fw_tx_credits = true,
> > > > .delay_unmap_buffer = false,
> > > > + .enable_threaded_napi = false,
> > > > },
> > > > {
> > > > .id = QCA9887_HW_1_0_VERSION,
> > > > @@ -181,6 +183,7 @@ static const struct ath10k_hw_params
> ath10k_hw_params_list[] = {
> > > > .hw_restart_disconnect = false,
> > > > .use_fw_tx_credits = true,
> > > > .delay_unmap_buffer = false,
> > > > + .enable_threaded_napi = false,
> > > > },
> > > > {
> > > > .id = QCA6174_HW_3_2_VERSION,
> > > > @@ -217,6 +220,7 @@ static const struct ath10k_hw_params
> ath10k_hw_params_list[] = {
> > > > .hw_restart_disconnect = false,
> > > > .use_fw_tx_credits = true,
> > > > .delay_unmap_buffer = false,
> > > > + .enable_threaded_napi = false,
> > > > },
> > > > {
> > > > .id = QCA6174_HW_2_1_VERSION,
> > > > @@ -257,6 +261,7 @@ static const struct ath10k_hw_params
> ath10k_hw_params_list[] = {
> > > > .hw_restart_disconnect = false,
> > > > .use_fw_tx_credits = true,
> > > > .delay_unmap_buffer = false,
> > > > + .enable_threaded_napi = false,
> > > > },
> > > > {
> > > > .id = QCA6174_HW_2_1_VERSION,
> > > > @@ -297,6 +302,7 @@ static const struct ath10k_hw_params
> ath10k_hw_params_list[] = {
> > > > .hw_restart_disconnect = false,
> > > > .use_fw_tx_credits = true,
> > > > .delay_unmap_buffer = false,
> > > > + .enable_threaded_napi = false,
> > > > },
> > > > {
> > > > .id = QCA6174_HW_3_0_VERSION,
> > > > @@ -337,6 +343,7 @@ static const struct ath10k_hw_params
> ath10k_hw_params_list[] = {
> > > > .hw_restart_disconnect = false,
> > > > .use_fw_tx_credits = true,
> > > > .delay_unmap_buffer = false,
> > > > + .enable_threaded_napi = false,
> > > > },
> > > > {
> > > > .id = QCA6174_HW_3_2_VERSION,
> > > > @@ -381,6 +388,7 @@ static const struct ath10k_hw_params
> ath10k_hw_params_list[] = {
> > > > .hw_restart_disconnect = false,
> > > > .use_fw_tx_credits = true,
> > > > .delay_unmap_buffer = false,
> > > > + .enable_threaded_napi = false,
> > > > },
> > > > {
> > > > .id = QCA99X0_HW_2_0_DEV_VERSION,
> > > > @@ -427,6 +435,7 @@ static const struct ath10k_hw_params
> ath10k_hw_params_list[] = {
> > > > .hw_restart_disconnect = false,
> > > > .use_fw_tx_credits = true,
> > > > .delay_unmap_buffer = false,
> > > > + .enable_threaded_napi = false,
> > > > },
> > > > {
> > > > .id = QCA9984_HW_1_0_DEV_VERSION,
> > > > @@ -480,6 +489,7 @@ static const struct ath10k_hw_params
> ath10k_hw_params_list[] = {
> > > > .hw_restart_disconnect = false,
> > > > .use_fw_tx_credits = true,
> > > > .delay_unmap_buffer = false,
> > > > + .enable_threaded_napi = false,
> > > > },
> > > > {
> > > > .id = QCA9888_HW_2_0_DEV_VERSION,
> > > > @@ -530,6 +540,7 @@ static const struct ath10k_hw_params
> ath10k_hw_params_list[] = {
> > > > .hw_restart_disconnect = false,
> > > > .use_fw_tx_credits = true,
> > > > .delay_unmap_buffer = false,
> > > > + .enable_threaded_napi = false,
> > > > },
> > > > {
> > > > .id = QCA9377_HW_1_0_DEV_VERSION,
> > > > @@ -570,6 +581,7 @@ static const struct ath10k_hw_params
> ath10k_hw_params_list[] = {
> > > > .hw_restart_disconnect = false,
> > > > .use_fw_tx_credits = true,
> > > > .delay_unmap_buffer = false,
> > > > + .enable_threaded_napi = false,
> > > > },
> > > > {
> > > > .id = QCA9377_HW_1_1_DEV_VERSION,
> > > > @@ -612,6 +624,7 @@ static const struct ath10k_hw_params
> ath10k_hw_params_list[] = {
> > > > .hw_restart_disconnect = false,
> > > > .use_fw_tx_credits = true,
> > > > .delay_unmap_buffer = false,
> > > > + .enable_threaded_napi = false,
> > > > },
> > > > {
> > > > .id = QCA9377_HW_1_1_DEV_VERSION,
> > > > @@ -645,6 +658,7 @@ static const struct ath10k_hw_params
> ath10k_hw_params_list[] = {
> > > > .hw_restart_disconnect = false,
> > > > .use_fw_tx_credits = true,
> > > > .delay_unmap_buffer = false,
> > > > + .enable_threaded_napi = false,
> > > > },
> > > > {
> > > > .id = QCA4019_HW_1_0_DEV_VERSION,
> > > > @@ -692,6 +706,7 @@ static const struct ath10k_hw_params
> ath10k_hw_params_list[] = {
> > > > .hw_restart_disconnect = false,
> > > > .use_fw_tx_credits = true,
> > > > .delay_unmap_buffer = false,
> > > > + .enable_threaded_napi = false,
> > > > },
> > > > {
> > > > .id = WCN3990_HW_1_0_DEV_VERSION,
> > > > @@ -725,6 +740,7 @@ static const struct ath10k_hw_params
> ath10k_hw_params_list[] = {
> > > > .hw_restart_disconnect = true,
> > > > .use_fw_tx_credits = false,
> > > > .delay_unmap_buffer = true,
> > > > + .enable_threaded_napi = true,
> > > > },
> > > > };
> > > >
> > > > diff --git a/drivers/net/wireless/ath/ath10k/hw.h
> b/drivers/net/wireless/ath/ath10k/hw.h
> > > > index 9643031a4427a..adf3076b96503 100644
> > > > --- a/drivers/net/wireless/ath/ath10k/hw.h
> > > > +++ b/drivers/net/wireless/ath/ath10k/hw.h
> > > > @@ -639,6 +639,8 @@ struct ath10k_hw_params {
> > > > bool use_fw_tx_credits;
> > > >
> > > > bool delay_unmap_buffer;
> > > > +
> > > > + bool enable_threaded_napi;
> > > > };
> > > >
> > > > struct htt_resp;
> > > > diff --git a/drivers/net/wireless/ath/ath10k/snoc.c
> b/drivers/net/wireless/ath/ath10k/snoc.c
> > > > index cfcb759a87dea..b94150fb6ef06 100644
> > > > --- a/drivers/net/wireless/ath/ath10k/snoc.c
> > > > +++ b/drivers/net/wireless/ath/ath10k/snoc.c
> > > > @@ -927,6 +927,9 @@ static int ath10k_snoc_hif_start(struct ath10k
> *ar)
> > > >
> > > > bitmap_clear(ar_snoc->pending_ce_irqs, 0, CE_COUNT_MAX);
> > > >
> > > > + if (ar->hw_params.enable_threaded_napi)
> > > > + dev_set_threaded(&ar->napi_dev, true);
> > > > +
> > > > ath10k_core_napi_enable(ar);
> > > > ath10k_snoc_irq_enable(ar);
> > > > ath10k_snoc_rx_post(ar);
> > > > --
> > > > 2.39.0.314.g84b9a713c41-goog
> > > >
> > >
> > >
> > > --
> > > This song goes out to all the folk that thought Stadia would work:
> > >
> https://www.linkedin.com/posts/dtaht_the-mushroom-song-activity-6981366665607352320-FXtz
> > > Dave Täht CEO, TekLibre, LLC
>
>
>
> --
> This song goes out to all the folk that thought Stadia would work:
>
> https://www.linkedin.com/posts/dtaht_the-mushroom-song-activity-6981366665607352320-FXtz
> Dave Täht CEO, TekLibre, LLC
> _______________________________________________
> Make-wifi-fast mailing list
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