[PATCH] drm/amdgpu: Add kernel parameter to force no xgmi

Thu Oct 29 18:08:17 UTC 2020

[AMD Public Use]

Will do Luben. Thanks for the recommendation.

> -----Original Message-----
> From: Tuikov, Luben <Luben.Tuikov at amd.com>
> Sent: Thursday, October 29, 2020 12:15 PM
> To: Sierra Guiza, Alejandro (Alex) <Alex.Sierra at amd.com>; Koenig, Christian
> <Christian.Koenig at amd.com>; amd-gfx at lists.freedesktop.org
> Subject: Re: [PATCH] drm/amdgpu: Add kernel parameter to force no xgmi
> 
> On 2020-10-28 15:09, Sierra Guiza, Alejandro (Alex) wrote:
> > [AMD Public Use]
> >
> > Please ignore this patch, it should be in a different branch. As PCIe p2p is
> not supported in upstream.
> 
> No problem, but if you do add it elsewhere, please use something more
> specific, like
> 
> 	amdgpu_xgmi_p2p
> 
> as the (positive-controlled) flag, since more generic flags could be added
> later, to control a more encompassing behaviour.
> 
> Regards,
> Luben
> 
> >
> > Regards,
> > Alex Sierra
> >
> >> -----Original Message-----
> >> From: amd-gfx <amd-gfx-bounces at lists.freedesktop.org> On Behalf Of
> >> Sierra Guiza, Alejandro (Alex)
> >> Sent: Wednesday, October 28, 2020 1:09 PM
> >> To: Koenig, Christian <Christian.Koenig at amd.com>; amd-
> >> gfx at lists.freedesktop.org
> >> Subject: Re: [PATCH] drm/amdgpu: Add kernel parameter to force no
> >> xgmi
> >>
> >>
> >> On 10/28/2020 9:58 AM, Christian König wrote:
> >>> Am 28.10.20 um 15:55 schrieb Alex Sierra:
> >>>> By enabling this parameter, the system will be forced to use pcie
> >>>> interface only for p2p transactions.
> >>>
> >>> Better name that amdgpu_xgmi with a default value of enabled.
> >>>
> >>> Or maybe add another bit value for amdgpu_vm_debug instead.
> >>
> >> Ack
> >>
> >> Regards,
> >> Alex Sierra
> >>
> >>>
> >>>
> >>>>
> >>>> Signed-off-by: Alex Sierra <alex.sierra at amd.com>
> >>>> ---
> >>>>   drivers/gpu/drm/amd/amdgpu/amdgpu.h        | 1 +
> >>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 2 +-
> >>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c    | 9 +++++++++
> >>>>   3 files changed, 11 insertions(+), 1 deletion(-)
> >>>>
> >>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> >>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> >>>> index ba65d4f2ab67..3645f00e9f61 100644
> >>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> >>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> >>>> @@ -188,6 +188,7 @@ extern int amdgpu_discovery;
> >>>>   extern int amdgpu_mes;
> >>>>   extern int amdgpu_noretry;
> >>>>   extern int amdgpu_force_asic_type;
> >>>> +extern int amdgpu_force_no_xgmi;
> >>>>   #ifdef CONFIG_HSA_AMD
> >>>>   extern int sched_policy;
> >>>>   extern bool debug_evictions;
> >>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> >>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> >>>> index 1fe850e0a94d..0a5d97a84017 100644
> >>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> >>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> >>>> @@ -2257,7 +2257,7 @@ static int amdgpu_device_ip_init(struct
> >>>> amdgpu_device *adev)
> >>>>       if (r)
> >>>>           goto init_failed;
> >>>>   -    if (adev->gmc.xgmi.num_physical_nodes > 1)
> >>>> +    if (!amdgpu_force_no_xgmi && adev-
> >>> gmc.xgmi.num_physical_nodes >
> >>>> +1)
> >>>
> >>> Mhm, this will most likely cause problems. You still need to add the
> >>> device to the hive because otherwise GPU won't work.
> >>
> >> What kind of problems? So far, I have validated this using a system
> >> with multiple devices and running ./rocm_bandwidth_test -t. With and
> >> without the parameter set.
> >>
> >> Regards,
> >> Alex Sierra
> >>
> >>>
> >>> Apart from that sounds like a good idea in general.
> >>>
> >>> Christian.
> >>>
> >>>>           amdgpu_xgmi_add_device(adev);
> >>>>       amdgpu_amdkfd_device_init(adev);
> >>>>   diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> >>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> >>>> index 4b78ecfd35f7..22485067cf31 100644
> >>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> >>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> >>>> @@ -160,6 +160,7 @@ int amdgpu_force_asic_type = -1;
> >>>>   int amdgpu_tmz = 0;
> >>>>   int amdgpu_reset_method = -1; /* auto */
> >>>>   int amdgpu_num_kcq = -1;
> >>>> +int amdgpu_force_no_xgmi = 0;
> >>>>     struct amdgpu_mgpu_info mgpu_info = {
> >>>>       .mutex = __MUTEX_INITIALIZER(mgpu_info.mutex),
> >>>> @@ -522,6 +523,14 @@ module_param_named(ras_enable,
> >>>> amdgpu_ras_enable, int, 0444);
> >>>>   MODULE_PARM_DESC(ras_mask, "Mask of RAS features to enable
> >> (default
> >>>> 0xffffffff), only valid when ras_enable == 1");
> >>>>   module_param_named(ras_mask, amdgpu_ras_mask, uint, 0444);
> >>>>   +/**
> >>>> + * DOC: force_no_xgmi (uint)
> >>>> + * Forces not to use xgmi interface (0 = disable, 1 = enable).
> >>>> + * Default is 0 (disabled).
> >>>> + */
> >>>> +MODULE_PARM_DESC(force_no_xgmi, "Force not to use xgmi
> >> interface");
> >>>> +module_param_named(force_no_xgmi, amdgpu_force_no_xgmi,
> int,
> >> 0600);
> >>>> +
> >>>>   /**
> >>>>    * DOC: si_support (int)
> >>>>    * Set SI support driver. This parameter works after set config
> >>>> CONFIG_DRM_AMDGPU_SI. For SI asic, when radeon driver is
> enabled,
> >>>
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