[PATCH v1 0/9] Enable SMP for pc386 based bsps

Tue Jun 2 07:22:28 UTC 2020

Hi Joel,

Yes, that should be the case in patch 5/9.
There, the addition to cpukit/score/cpu/i386/include/rtems/score/cpu.h should be the struct the ticket is talking about.

Best regards,

   Jan

From: Joel Sherrill [mailto:joel at rtems.org]
Sent: Monday, June 1, 2020 10:58 PM
To: Sommer, Jan
Cc: rtems-devel at rtems.org
Subject: Re: [PATCH v1 0/9] Enable SMP for pc386 based bsps

Thank you for taking the time and energy to do this. It

Did your patch comments close https://devel.rtems.org/ticket/3335?

On Sun, May 31, 2020 at 9:23 AM Jan Sommer <jan.sommer at dlr.de<mailto:jan.sommer at dlr.de>> wrote:
Hello,

Here is a patch set which should enable SMP again for the pc386-based BSPs (mainly tested with pc686).
So far I only tested it with qemu. Tests on real hardware are pending.
To me it looks like there are no regressions for the standard non-SMP version of the BSP, but it is difficult to say for sure.
Subsequent runs of the testsuite with a current master build already produce different numbers of failed/timeout/invalid tests.

However, even with the patch set applied the amount of passed tests continues to range from 550-557 and the failed/timeout/invalid tests seem to be generally the same.
Regarding smptests, the current status with qemu-4.2.0 and 4 cores looks like this:

Passed:        55
Failed:         1
User Input:     0
Expected Fail:  0
Indeterminate:  0
Benchmark:      0
Timeout:        2
Invalid:        1
Wrong Version:  0
Wrong Build:    0
Wrong Tools:    0
-----------------
Total:         59
Failures:
 smpatomic01.exe
Timeouts:
 smpclock01.exe
 smpopenmp01.exe
Invalid:
 smpfatal09.exe

Some details on the missing tests:
-----------------------------------
smpfatal09: This test actually does pass, but because the fatal error handler is executed before the console is initialized, no output is produced.

smpclock01.exe: Here CPU0 disables its local interrupts and waits for a barrier release of CPU1. This means it doesn't handle timer interrupts anymore and doesn't send corresponding IPIs to other CPUs.
At the same time CPU1 is waiting for a timer event before releasing the barrier. Any hints how to resolve this are very welcome.

smpatomic01: This test seems very large and a bit complicated to me. I will have a look at it next, but any suggestions are welcome. It fails with this information:
] === atomic or/and test case ===
] worker 0 value: 1
] worker 1 value: 0
] atomic value: expected = 1, actual = 1
] ../../../../../../smp-refex-rtems/c/src/../../testsuites/smptests/smpatomic01/init.c: 404 n - s < LONG_MAX
]
] *** FATAL ***

smpopenmp01: I don't know more about openmp then what is on wikipedia. It has currently a low priority for me.

Some details regarding the patch set:
-------------------------------------

- The first 3 commits are basically cleaning the original start16.S to be used for starting the application processors only and updating the general bring up infrastructure.
- The next 2 commits are updating the low level context switch and isr handling in assembly. I used the ARM implementation as a template and tried to stay comparably close to it.
- The last 4 commits are smaller changes made after debugging certain test cases.

My next step would be to test the SMP functionality on HW. My goal would be to get the final revision published as part of the RTEMS5 release.
If you would like to see any logs from a testsuite run with certain parameters, just tell me.

Best regards,

    Jan

Jan Sommer (9):
  bsp/pc386: Fix Makefile for building with SMP
  bsp/pc386: Turn start16.S into a startAP.S
  bsp/pc386: Update GDT to work for SMP
  bsp/pc386: Update context switch and restore
  bsp/pc386: Define interrupt stack frame for smp
  bsps/pc386: Fix Clock_isr for SMP
  bsps/pc386: Separate smp API functions. Makes smpfatal08 link
  smpsignal01: Change state before sending the signal
  bsp/pc386: Disable interrupt nesting for job handler

 bsps/i386/include/bsp/smp-imps.h                   |   3 +
 bsps/i386/pc386/clock/ckinit.c                     |   2 +-
 bsps/i386/pc386/include/bsp.h                      |   7 +
 bsps/i386/pc386/include/bsp/tblsizes.h             |   8 +-
 bsps/i386/pc386/start/bspsmp.c                     |  43 ++++
 bsps/i386/pc386/start/getcpuid.c                   |  22 --
 bsps/i386/pc386/start/ldsegs.S                     |   4 +-
 bsps/i386/pc386/start/smp-imps.c                   |  79 ++++---
 bsps/i386/pc386/start/start16.S                    | 254 ---------------------
 bsps/i386/pc386/start/startAP.S                    | 118 ++++++++++
 bsps/i386/shared/irq/irq_asm.S                     | 102 +++++----
 c/src/lib/libbsp/i386/pc386/Makefile.am            |   8 +-
 cpukit/score/cpu/i386/cpu_asm.S                    |  74 ++++--
 cpukit/score/cpu/i386/include/rtems/asm.h          |  26 +++
 cpukit/score/cpu/i386/include/rtems/score/cpu.h    |  32 +--
 .../score/cpu/i386/include/rtems/score/cpuimpl.h   |   2 +
 testsuites/smptests/smpsignal01/init.c             |   2 +-
 17 files changed, 382 insertions(+), 404 deletions(-)
 create mode 100644 bsps/i386/pc386/start/bspsmp.c
 delete mode 100644 bsps/i386/pc386/start/getcpuid.c
 delete mode 100644 bsps/i386/pc386/start/start16.S
 create mode 100644 bsps/i386/pc386/start/startAP.S

--
2.12.3

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