Re: 答复: 答复: 答复: [PATCH] drm/amdgpu: adjust gtt memory size
Christian König
deathsimple at vodafone.de
Thu Jul 21 12:04:25 UTC 2016
> we can add people in if necessary here. so the initial though of this
> change is with latest big memory GPU released, the remote memory goes
> very large, like Polaris10.
>
> According to the windows WDDM, remote memory size is half of the
> system memory, I don't know what was discussed before, Please let me
> know if there're use case indeed need that big of remote memory.
>
Well that is at least something that makes sense.
Previous discussions where always settled around making GART bigger than
VRAM and not the other way around.
Anyway I think a prerequisite to this is actually allowing half of
system memory to be allocated for GART and I'm not sure if that is
currently the case. TTM has a limitation for that as well, but I off
hand don't remember how high much it was.
I think we should use the same value which TTM uses for the upper limit
here.
Regards,
Christian.
Am 21.07.2016 um 13:56 schrieb Wang, Qingqing:
>
> alright, I didn't realize you're not in that thread.
>
> we can add people in if necessary here. so the initial though of this
> change is with latest big memory GPU released, the remote memory goes
> very large, like Polaris10.
>
> According to the windows WDDM, remote memory size is half of the
> system memory, I don't know what was discussed before, Please let me
> know if there're use case indeed need that big of remote memory.
>
> ------------------------------------------------------------------------
> *发件人:* Christian König <deathsimple at vodafone.de>
> *发送时间:* 2016年7月21日 19:48:17
> *收件人:* Wang, Qingqing; amd-gfx at lists.freedesktop.org
> *主题:* Re: 答复: 答复: [PATCH] drm/amdgpu: adjust gtt memory size
> Am 21.07.2016 um 13:15 schrieb Wang, Qingqing:
>>
>> Actually that discussion was held long ago internally but we never
>> got a conclusion on this IIRC. So we should probably continue the
>> discussion on this thread now.
>>
>> -there is a thread for this topic yesterday, some people are not in
>> amd-gfx mail list, we'd better discuss in the internal thread.
>>
> No, exactly for this reason we have the public mailing list. I for
> example wasn't part of the internal thread either.
>
> Christian.
>
>> ------------------------------------------------------------------------
>> *发件人:* Christian König <deathsimple at vodafone.de>
>> *发送时间:* 2016年7月21日 17:48:41
>> *收件人:* Wang, Qingqing; amd-gfx at lists.freedesktop.org
>> *主题:* Re: 答复: [PATCH] drm/amdgpu: adjust gtt memory size
>> Am 21.07.2016 um 11:16 schrieb Wang, Qingqing:
>>>
>>> This doesn't work on 32bit systems since totalram is a long (IIRC) and
>>> so this will certainly overflow.
>>>
>>> -- can you be more specific, how could the overflow happen?
>>>
>>
>> Both values are 32bit on a 32bit system, so as soon as you have more
>> than 4GB installed this will overflow.
>>
>> You need to cast the long to a 64bit value to avoid that.
>>
>>>
>>> Additional if I remember correctly we didn't ended the discussion on
>>> what to do here with a conclusion.
>>>
>>> -- ok, since it happens in anther mail list, we should stop talking
>>> about it here, you can send out your ideas there.
>>>
>>
>> Actually that discussion was held long ago internally but we never
>> got a conclusion on this IIRC. So we should probably continue the
>> discussion on this thread now.
>>
>> Regards,
>> Christian.
>>
>>> ------------------------------------------------------------------------
>>> *发件人:* amd-gfx <amd-gfx-bounces at lists.freedesktop.org> 代表 Christian
>>> König <deathsimple at vodafone.de>
>>> *发送时间:* 2016年7月21日 16:53:05
>>> *收件人:* Wang, Qingqing; amd-gfx at lists.freedesktop.org
>>> *主题:* Re: [PATCH] drm/amdgpu: adjust gtt memory size
>>> Am 21.07.2016 um 09:46 schrieb Ken Wang:
>>> > Change-Id: If00d5b97ba9e30f9b7f68fdfc134a0f8b3ad2add
>>> > Signed-off-by: Ken Wang <Qingqing.Wang at amd.com>
>>> > ---
>>> > drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c | 7 ++++++-
>>> > drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c | 7 ++++++-
>>> > 2 files changed, 12 insertions(+), 2 deletions(-)
>>> >
>>> > diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c
>>> b/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c
>>> > index a3b6048..0b095d5 100644
>>> > --- a/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c
>>> > +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c
>>> > @@ -336,6 +336,11 @@ static int gmc_v7_0_mc_init(struct
>>> amdgpu_device *adev)
>>> > {
>>> > u32 tmp;
>>> > int chansize, numchan;
>>> > + u64 sysmem_size;
>>> > + struct sysinfo si;
>>> > +
>>> > + si_meminfo(&si);
>>> > + sysmem_size = si.totalram * si.mem_unit;
>>>
>>> This doesn't work on 32bit systems since totalram is a long (IIRC) and
>>> so this will certainly overflow.
>>>
>>> Additional if I remember correctly we didn't ended the discussion on
>>> what to do here with a conclusion.
>>>
>>> Regards,
>>> Christian.
>>>
>>> >
>>> > /* Get VRAM informations */
>>> > tmp = RREG32(mmMC_ARB_RAMCFG);
>>> > @@ -392,7 +397,7 @@ static int gmc_v7_0_mc_init(struct
>>> amdgpu_device *adev)
>>> > * size equal to the 1024 or vram, whichever is larger.
>>> > */
>>> > if (amdgpu_gart_size == -1)
>>> > - adev->mc.gtt_size = max((1024ULL << 20),
>>> adev->mc.mc_vram_size);
>>> > + adev->mc.gtt_size = max((1024ULL << 20),
>>> min(adev->mc.mc_vram_size, sysmem_size/2));
>>> > else
>>> > adev->mc.gtt_size = (uint64_t)amdgpu_gart_size << 20;
>>> >
>>> > diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c
>>> b/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c
>>> > index 02b6872..790bf7a 100644
>>> > --- a/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c
>>> > +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c
>>> > @@ -413,6 +413,11 @@ static int gmc_v8_0_mc_init(struct
>>> amdgpu_device *adev)
>>> > {
>>> > u32 tmp;
>>> > int chansize, numchan;
>>> > + u64 sysmem_size;
>>> > + struct sysinfo si;
>>> > +
>>> > + si_meminfo(&si);
>>> > + sysmem_size = si.totalram * si.mem_unit;
>>> >
>>> > /* Get VRAM informations */
>>> > tmp = RREG32(mmMC_ARB_RAMCFG);
>>> > @@ -469,7 +474,7 @@ static int gmc_v8_0_mc_init(struct
>>> amdgpu_device *adev)
>>> > * size equal to the 1024 or vram, whichever is larger.
>>> > */
>>> > if (amdgpu_gart_size == -1)
>>> > - adev->mc.gtt_size = max((1024ULL << 20),
>>> adev->mc.mc_vram_size);
>>> > + adev->mc.gtt_size = max((1024ULL << 20),
>>> min(adev->mc.mc_vram_size, sysmem_size/2));
>>> > else
>>> > adev->mc.gtt_size = (uint64_t)amdgpu_gart_size << 20;
>>> >
>>>
>>>
>>> _______________________________________________
>>> amd-gfx mailing list
>>> amd-gfx at lists.freedesktop.org
>>> https://lists.freedesktop.org/mailman/listinfo/amd-gfx
>>
>>
>
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