From: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
To: Rob Clark <robdclark@gmail.com>
Cc: "Isaac J. Manjarres" <isaacm@codeaurora.org>,
Will Deacon <will@kernel.org>, Joerg Roedel <joro@8bytes.org>,
Akhil P Oommen <akhilpo@codeaurora.org>,
"\" <iommu@lists.linux-foundation.org>,
<linux-arm-kernel@lists.infradead.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-arm-msm <linux-arm-msm@vger.kernel.org>,
freedreno <freedreno@lists.freedesktop.org>,
Kristian H Kristensen <hoegsberg@google.com>,
Sean Paul <sean@poorly.run>, David Airlie <airlied@linux.ie>,
Daniel Vetter <daniel@ffwll.ch>,
dri-devel" <dri-devel@lists.freedesktop.org>,
Jordan Crouse <jordan@cosmicpenguin.net>,
Robin Murphy <robin.murphy@arm.com>
Subject: Re: [PATCH 2/3] iommu/io-pgtable-arm: Add IOMMU_LLC page protection flag
Date: Wed, 17 Mar 2021 15:03:16 +0530 [thread overview]
Message-ID: <d44fc38c038be1165aa8f4212bd9c91f@codeaurora.org> (raw)
In-Reply-To: <CAF6AEGuc5i9hMtfU3HSpLVWi_e=emJTPLqntzJfAH69dO_gagA@mail.gmail.com>
Hi Rob,
On 2021-03-16 22:46, Rob Clark wrote:
<snip>...
>> > >
>> > > When the GPU has a buffer mapped with IOMMU_LLC, is the buffer also mapped
>> > > into the CPU and with what attributes? Rob said "writecombine for
>> > > everything" -- does that mean ioremap_wc() / MEMREMAP_WC?
>> >
>> > Currently userspace asks for everything WC, so pgprot_writecombine()
>> >
>> > The kernel doesn't enforce this, but so far provides no UAPI to do
>> > anything useful with non-coherent cached mappings (although there is
>> > interest to support this)
>> >
>>
>> btw, I'm looking at a benchmark (gl_driver2_off) where (after some
>> other in-flight optimizations land) we end up bottlenecked on writing
>> to WC cmdstream buffers. I assume in the current state, WC goes all
>> the way to main memory rather than just to system cache?
>>
>
> oh, I guess this (mentioned earlier in thread) is what I really want
> for this benchmark:
>
> https://android-review.googlesource.com/c/kernel/common/+/1549097/3
>
You can also check if the system cache lines are allocated for GPU
or not with patch in https://crrev.com/c/2766723
With the above patch applied,
cat /sys/kernel/debug/llcc_stats/llcc_scid_status
The SCIDs for GPU are listed in include/linux/soc/qcom/llcc-qcom.h
Thanks,
Sai
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next prev parent reply other threads:[~2021-03-17 9:33 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-11 14:15 [PATCH 0/3] iommu/drm/msm: Allow non-coherent masters to use system cache Sai Prakash Ranjan
2021-01-11 14:15 ` [PATCH 1/3] iommu/io-pgtable: Rename last-level cache quirk to IO_PGTABLE_QUIRK_PTW_LLC Sai Prakash Ranjan
2021-01-11 14:15 ` [PATCH 2/3] iommu/io-pgtable-arm: Add IOMMU_LLC page protection flag Sai Prakash Ranjan
2021-01-29 9:05 ` Will Deacon
2021-01-29 9:42 ` Sai Prakash Ranjan
2021-02-01 11:15 ` Will Deacon
2021-02-01 16:20 ` Rob Clark
2021-02-01 18:20 ` Jordan Crouse
2021-02-02 6:26 ` Sai Prakash Ranjan
2021-02-03 21:46 ` Will Deacon
2021-02-03 22:14 ` Rob Clark
2021-03-16 17:04 ` Rob Clark
2021-03-16 17:16 ` Rob Clark
2021-03-17 9:33 ` Sai Prakash Ranjan [this message]
2021-03-25 18:36 ` Rob Clark
2021-02-05 12:08 ` Sai Prakash Ranjan
2021-03-09 6:40 ` Sai Prakash Ranjan
2021-03-25 17:33 ` Will Deacon
2021-06-30 10:07 ` Sai Prakash Ranjan
2021-02-02 6:28 ` Sai Prakash Ranjan
2021-01-11 14:15 ` [PATCH 3/3] drm/msm: Use IOMMU_LLC page protection flag to map gpu buffers Sai Prakash Ranjan
2021-01-20 5:18 ` [PATCH 0/3] iommu/drm/msm: Allow non-coherent masters to use system cache Sai Prakash Ranjan
2021-01-29 8:53 ` Sai Prakash Ranjan
2021-07-28 14:00 ` Georgi Djakov
2021-07-29 4:38 ` Sai Prakash Ranjan
2021-08-02 10:55 ` Will Deacon
2021-08-02 15:08 ` [Freedreno] " Rob Clark
2021-08-02 15:14 ` Will Deacon
2021-08-03 1:36 ` Rob Clark
2021-08-09 14:56 ` Will Deacon
2021-08-09 16:57 ` Rob Clark
2021-08-09 17:05 ` Will Deacon
2021-08-09 17:18 ` Rob Clark
2021-08-09 17:40 ` Will Deacon
2021-08-09 17:47 ` Sai Prakash Ranjan
2021-08-09 18:07 ` Rob Clark
2021-08-09 18:10 ` Sai Prakash Ranjan
2021-08-09 18:30 ` Rob Clark
2021-08-09 18:32 ` Sai Prakash Ranjan
2021-08-10 9:16 ` Will Deacon
2021-08-10 9:54 ` Sai Prakash Ranjan
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