[Performance regression] BCM4359/9 on S905X2
Christian Hewitt
christianshewitt at gmail.com
Thu Apr 6 10:07:26 PDT 2023
> On 6 Apr 2023, at 8:35 pm, Marc Gonzalez <marc.w.gonzalez at free.fr> wrote:
>
> On 04/04/2023 23:06, Martin Blumenstingl wrote:
>
>> Hi Marc,
>
> Hello Martin :)
>
>> On Tue, Apr 4, 2023 at 6:09 PM Marc Gonzalez wrote:
>>
>>> bus-width = <4>;
>>> cap-sd-highspeed;
>>> cap-mmc-highspeed;
>>> max-frequency = <100000000>;
>>
>> I would start by comparing the bus mode. You can get it from
>> /sys/kernel/debug/mmc2/ios
>> On the vendor kernel it should be in /sys/kernel/debug/sdio/ios (or
>> similar, I'm typing this from the top of my head).
>> It will give you insights on the clock and timing that has been
>> negotiated between the host and card.
>>
>> From this information you can get the maximum bus speed, e.g. from [0]
>> Please note that any card will add overhead for communication, so bus
>> speed will not be equal to wifi throughput.
>
> For the vendor kernel:
>
> /sys/kernel/debug/sdio/sdio:0001/state:0x00000001
> /sys/kernel/debug/sdio/clock:200000000
> /sys/kernel/debug/sdio/ios:clock: 200000000 Hz
> /sys/kernel/debug/sdio/ios:actual clock: 199999997 Hz
> /sys/kernel/debug/sdio/ios:vdd: 21 (3.3 ~ 3.4 V)
> /sys/kernel/debug/sdio/ios:bus mode: 2 (push-pull)
> /sys/kernel/debug/sdio/ios:chip select: 0 (don't care)
> /sys/kernel/debug/sdio/ios:power mode: 1 (up)
> /sys/kernel/debug/sdio/ios:bus width: 2 (4 bits)
> /sys/kernel/debug/sdio/ios:timing spec: 6 (sd uhs SDR104)
> /sys/kernel/debug/sdio/ios:signal voltage: 1 (1.80 V)
> /sys/kernel/debug/sdio/ios:driver type: 0 (driver type B)
>
>
> For mainline:
>
> /sys/kernel/debug/mmc2/mmc2:0001/state:0x00000001
> /sys/kernel/debug/mmc2/err_stats:# Command Timeout Occurred: 0
> /sys/kernel/debug/mmc2/err_stats:# Command CRC Errors Occurred: 0
> /sys/kernel/debug/mmc2/err_stats:# Data Timeout Occurred: 0
> /sys/kernel/debug/mmc2/err_stats:# Data CRC Errors Occurred: 0
> /sys/kernel/debug/mmc2/err_stats:# Auto-Cmd Error Occurred: 0
> /sys/kernel/debug/mmc2/err_stats:# ADMA Error Occurred: 0
> /sys/kernel/debug/mmc2/err_stats:# Tuning Error Occurred: 0
> /sys/kernel/debug/mmc2/err_stats:# CMDQ RED Errors: 0
> /sys/kernel/debug/mmc2/err_stats:# CMDQ GCE Errors: 0
> /sys/kernel/debug/mmc2/err_stats:# CMDQ ICCE Errors: 0
> /sys/kernel/debug/mmc2/err_stats:# Request Timedout: 0
> /sys/kernel/debug/mmc2/err_stats:# CMDQ Request Timedout: 0
> /sys/kernel/debug/mmc2/err_stats:# ICE Config Errors: 0
> /sys/kernel/debug/mmc2/err_stats:# Controller Timedout errors: 0
> /sys/kernel/debug/mmc2/err_stats:# Unexpected IRQ errors: 0
> /sys/kernel/debug/mmc2/err_state:0
> /sys/kernel/debug/mmc2/clock:100000000
> /sys/kernel/debug/mmc2/caps2:0x00040000
> /sys/kernel/debug/mmc2/caps:0x40040105
> /sys/kernel/debug/mmc2/ios:clock: 100000000 Hz
> /sys/kernel/debug/mmc2/ios:actual clock: 99999999 Hz
> /sys/kernel/debug/mmc2/ios:vdd: 21 (3.3 ~ 3.4 V)
> /sys/kernel/debug/mmc2/ios:bus mode: 2 (push-pull)
> /sys/kernel/debug/mmc2/ios:chip select: 0 (don't care)
> /sys/kernel/debug/mmc2/ios:power mode: 2 (on)
> /sys/kernel/debug/mmc2/ios:bus width: 2 (4 bits)
> /sys/kernel/debug/mmc2/ios:timing spec: 5 (sd uhs SDR50)
> /sys/kernel/debug/mmc2/ios:signal voltage: 1 (1.80 V)
> /sys/kernel/debug/mmc2/ios:driver type: 0 (driver type B)
>
>
> The clock is indeed running twice as fast on the vendor system.
> And in SDR104 vs SDR50 mode.
>
> Adjusting mainline device tree...
>
>
> /sys/kernel/debug/mmc2/mmc2:0001/state:0x00000001
> /sys/kernel/debug/mmc2/err_stats:# Command Timeout Occurred: 0
> /sys/kernel/debug/mmc2/err_stats:# Command CRC Errors Occurred: 0
> /sys/kernel/debug/mmc2/err_stats:# Data Timeout Occurred: 0
> /sys/kernel/debug/mmc2/err_stats:# Data CRC Errors Occurred: 0
> /sys/kernel/debug/mmc2/err_stats:# Auto-Cmd Error Occurred: 0
> /sys/kernel/debug/mmc2/err_stats:# ADMA Error Occurred: 0
> /sys/kernel/debug/mmc2/err_stats:# Tuning Error Occurred: 0
> /sys/kernel/debug/mmc2/err_stats:# CMDQ RED Errors: 0
> /sys/kernel/debug/mmc2/err_stats:# CMDQ GCE Errors: 0
> /sys/kernel/debug/mmc2/err_stats:# CMDQ ICCE Errors: 0
> /sys/kernel/debug/mmc2/err_stats:# Request Timedout: 0
> /sys/kernel/debug/mmc2/err_stats:# CMDQ Request Timedout: 0
> /sys/kernel/debug/mmc2/err_stats:# ICE Config Errors: 0
> /sys/kernel/debug/mmc2/err_stats:# Controller Timedout errors: 0
> /sys/kernel/debug/mmc2/err_stats:# Unexpected IRQ errors: 0
> /sys/kernel/debug/mmc2/err_state:0
> /sys/kernel/debug/mmc2/clock:200000000
> /sys/kernel/debug/mmc2/caps2:0x00040000
> /sys/kernel/debug/mmc2/caps:0x40080105
> /sys/kernel/debug/mmc2/ios:clock: 200000000 Hz
> /sys/kernel/debug/mmc2/ios:actual clock: 199999997 Hz
> /sys/kernel/debug/mmc2/ios:vdd: 21 (3.3 ~ 3.4 V)
> /sys/kernel/debug/mmc2/ios:bus mode: 2 (push-pull)
> /sys/kernel/debug/mmc2/ios:chip select: 0 (don't care)
> /sys/kernel/debug/mmc2/ios:power mode: 2 (on)
> /sys/kernel/debug/mmc2/ios:bus width: 2 (4 bits)
> /sys/kernel/debug/mmc2/ios:timing spec: 6 (sd uhs SDR104)
> /sys/kernel/debug/mmc2/ios:signal voltage: 1 (1.80 V)
> /sys/kernel/debug/mmc2/ios:driver type: 0 (driver type B)
>
>
> # curl -o /dev/null http://192.168.1.254:8095/fixed/1G
> % Total % Received % Xferd Average Speed Time Time Time Current
> Dload Upload Total Spent Left Speed
> 100 1024M 100 1024M 0 0 9747k 0 0:01:47 0:01:47 --:--:-- 9544k
>
> With this new setting, WiFi throughput increases 20%
> (from 60 Mbps to 75 Mbps).
>
> (Uggg, I've been using 10^9 for the amount transferred,
> but it looks to be 2^30 actually. Absolute speeds are
> actually 7% higher, but doesn't change the conclusion)
>
> I also noticed that I reported 11 MB/s (88 Mbps) at the beginning
> of this thread. This would point to a performance regression caused
> by my defconfig & device tree changes :(
>
>
>>> vendor DTS has the following child node:
>>>
>>> sdio {
>>> pinname = "sdio";
>>> ocr_avail = <0x200080>; /**VDD voltage 3.3 ~ 3.4 */
>>> /* max_req_size = <0x20000>; */ /**128KB*/
>>> max_req_size = <0x400>;
>>> card_type = <3>;
>>> /* 3:sdio device(ie:sdio-wifi),
>>> * 4:SD combo (IO+mem) card
>>> */
>>> dmode = "pio";
>>> };
>>>
>>> Maybe the vendor kernel uses the above information to "boost"
>>> the performance of the SDIO-based WiFi adapter?
>>
>> PIO is also what we support upstream with the
>> amlogic,dram-access-quirk; (which is enabled for &sd_emmc_a).
>> This suggests that the pinctrl trick that Neil mentioned is not used here.
>>
>> I assume that the wifi driver on the vendor kernel is the brcmdhd (out
>> of tree) driver, while mainline uses brcmfmac.
>
> Correct.
> hardware/wifi/broadcom/drivers/ap6xxx/bcmdhd.100.10.545.x
> vs
> drivers/net/wireless/broadcom/brcm80211/brcmfmac
>
>> One idea that comes to my mind is to enable the
>> amlogic,dram-access-quirk; (and use pio mode on the vendor kernel) for
>> eMMC or SD card and then compare read/write speeds. If they are
>> similar-ish then the wifi performance difference is likely caused by
>> the wifi driver (or in the opposite case: if read/write speeds on
>> mainline with amlogic,dram-access-quirk; perform worse than the vendor
>> kernel with pio mode then it's likely that it's a meson-gx-mmc driver
>> limitation).
>
> Thanks for the suggestion.
>
> Are you aware whether someone has tried running the bcmdhd driver
> on mainline?
https://gitlab.baylibre.com/baylibre/amlogic/atv/linux/-/commits/narmstrong/v5.1/aml/integ-5.1-bcmdhd
IIRC not long after this ^ support for BCM4359 was added to brcmfmac so
using bcmdhd wasn’t pursued. Neil?
Christian
> Thanks for the test suggestion.
>
>> From my work on the rtw88 SDIO wifi driver I can say that the
>> meson-gx-mmc driver can push (TX direction) at least 120Mbit/s.
>> I understand that this is half of what you get with the vendor kernel
>> - and that this is the wrong direction (you're testing RX while I'm
>> testing TX).
>> The point that I want to get across is: I think nobody has the one
>> answer why wifi performance is lower (personally I'm happy with having
>> it work at all, performance is second).
>> So it'll be a process to find the reason, and I think it requires
>> being creative due to the large amounts of different code (MMC driver,
>> wifi driver, additional patches...) between mainline and the vendor
>> kernel.
>
> I really appreciate you sharing this insight.
>
> Regards.
>
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