RE: [EXT] Re: latency: negative value?

[Jerry Huang <jerry.huang@nxp.com>]

Thanks a lot, Philippe.
Yes, my board is LayerScape ls1043ardb and ls1028ardb.
With the command "autotune", now the negative value issue is fixed.

>-----Original Message-----
>From: Philippe Gerum <rpm@xenomai.org>
>Sent: 2022年4月24日 17:01
>To: Jerry Huang <jerry.huang@nxp.com>
>Cc: xenomai@xenomai.org
>Subject: [EXT] Re: latency: negative value?
>
>Caution: EXT Email
>
>Jerry Huang via Xenomai <xenomai@xenomai.org> writes:
>
>> Hi, all guys,
>> Now I am using linux-dovetail/v5.15.6-dovetail1-rebase on my RDB board.
>> 1 . I am running latency command, but when I running command:
>> latency -t 1 -T 30
>> I got the negative value:
>> RTD|     -2.760|     -2.654|     -1.800|       0|     0|
>-2.760|     -1.400
>>
>> 2. Then, I got the solution from google:
>> Run command: xeno latency -T 20
>> I got:
>> RTD|     -1.360|     -1.235|     -0.040|       0|     0|
>-1.440|      0.440
>>
>> 3. then I update /proc/xenomai/latency value echo -1440 >
>> /proc/xenomai/latency
>>
>> 4. when I run xeno latency again, I got below result:
>> RTD|      5.240|      5.389|      6.640|       0|     0|
>5.040|      7.600
>>
>> 5. but when I run command again: latency -t 1 -T 30, I still got the
>> negative value:
>> RTD|     -2.760|     -2.652|     -1.760|       0|     0|
>-2.760|     -1.400
>>
>> So, How to fix the issue?
>
>The core timer needs to be calibrated, it looks like the default calibration values
>are too conservative for the performances of this board (is it from the
>Layerscape series?), especially for kernel thread/irq wakeups. This may help:
>
>https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fxenoma
>i.org%2Fdocumentation%2Fxenomai-3%2Fhtml%2Fman1%2Fautotune%2Finde
>x.html&amp;data=05%7C01%7Cjerry.huang%40nxp.com%7Ca824a0ef5f2b450
>7bda208da25d37342%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C1%7
>C637863887348669671%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAw
>MDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C2000%7C%7C%
>7C&amp;sdata=TQAEfC26EE5wmICrtJr%2Byej9aV00uXTbCraoMYalias%3D&a
>mp;reserved=0
>
>> And how to check the xenomai interrupt? I remember I can get the interrupt
>number through "cat /proc/xenomai/irq",but now I can't find it.
>>
>
>With Dovetail underneath, you just need to look at /proc/interrupts as usual.
>The 'oob' flag tells you whether the interrupt is handled by the real-time core
>in out-of-band mode (real-time).
Thanks, Philippe,
I can see my interrupt in /proc/interrupts with oob flag
98:      32454          0          0          0       MSI 134742016 Edge     oob  rteth0

>e.g. this is from an i.MX6QP SabreSD, we can see the per-CPU TWD being
>handled in oob mode for high-precision timing by the real-time domain. The
>proxy tick interrupt (315) is a synthetic IRQ created by Dovetail in order to
>relay some timer events to the common kernel at due date, since the real-time
>core manages the hardware for the whole system.
>
>~ # cat /proc/interrupts
>           CPU0       CPU1       CPU2       CPU3
> 24:          0          0          0          0     SIRQC  24
>Edge          in-band work
> 25:        567        292        381        676 GIC-0  29 Edge
>oob  twd
> 26:          0          0          0          0       GPC  55
>Level         i.MX Timer Tick
> 27:          0          0          0          0       GPC  94
>Level         arm-pmu
> 35:         50          0          0          0       GPC  26
>Level         2020000.serial
> 55:          0          0          0          0       GPC  81
>Level         20c0000.watchdog
> 67:          0          0          0          0       GPC   2
>Level         sdma
> 70:       1611          0          0          0       GPC 118
>Level         2188000.ethernet
> 71:          0          0          0          0       GPC 119
>Level         2188000.ethernet
> 72:          0          0          0          0       GPC  23
>Level         mmc1
> 73:        146          0          0          0       GPC  24
>Level         mmc2
> 74:         43          0          0          0       GPC  25
>Level         mmc3
> 75:          0          0          0          0       GPC  36
>Level         21a0000.i2c
> 76:          0          0          0          0       GPC  37
>Level         21a4000.i2c
> 77:          2          0          0          0       GPC  38
>Level         21a8000.i2c
> 87:          0          0          0          0       GPC  39
>Level         ahci-imx[2200000.sata]
> 95:          0          0          0          0  gpio-mxc   4
>Edge          Volume Up
> 96:          0          0          0          0  gpio-mxc   5
>Edge          Volume Down
>123:          0          0          0          0  gpio-mxc   0
>Edge          2198000.mmc cd
>125:          0          0          0          0  gpio-mxc   2
>Edge          2194000.mmc cd
>184:          0          0          0          0  gpio-mxc  29
>Edge          Power Button
>315:        429        160        364        546     SIRQC 315
>Edge          proxy tick
>IPI0:          0          0          0          0  CPU wakeup
>interrupts
>IPI1:          0          0          0          0  Timer broadcast
>interrupts
>IPI2:         37         40         27         23  Rescheduling
>interrupts
>IPI3:        470        944       1352       1809  Function call
>interrupts
>IPI4:          0          0          0          0  CPU stop
>interrupts
>IPI5:          0          0          0          0  IRQ work
>interrupts
>IPI6:          0          0          0          0  completion
>interrupts
>Err:          0
>
>--
>Philippe.