From: Daniel Vetter <daniel.vetter@ffwll.ch>
To: Huan Yang <link@vivo.com>
Cc: "Sumit Semwal" <sumit.semwal@linaro.org>,
"Benjamin Gaignard" <benjamin.gaignard@collabora.com>,
"Brian Starkey" <Brian.Starkey@arm.com>,
"John Stultz" <jstultz@google.com>,
"T.J. Mercier" <tjmercier@google.com>,
"Christian König" <christian.koenig@amd.com>,
linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org,
linaro-mm-sig@lists.linaro.org, linux-kernel@vger.kernel.org,
opensource.kernel@vivo.com
Subject: Re: [PATCH v2 0/5] Introduce DMA_HEAP_ALLOC_AND_READ_FILE heap flag
Date: Tue, 30 Jul 2024 10:56:31 +0200 [thread overview]
Message-ID: <Zqiqv7fomIp1IPS_@phenom.ffwll.local> (raw)
In-Reply-To: <20240730075755.10941-1-link@vivo.com>
On Tue, Jul 30, 2024 at 03:57:44PM +0800, Huan Yang wrote:
> UDMA-BUF step:
> 1. memfd_create
> 2. open file(buffer/direct)
> 3. udmabuf create
> 4. mmap memfd
> 5. read file into memfd vaddr
Yeah this is really slow and the worst way to do it. You absolutely want
to start _all_ the io before you start creating the dma-buf, ideally with
everything running in parallel. But just starting the direct I/O with
async and then creating the umdabuf should be a lot faster and avoid
needlessly serialization operations.
The other issue is that the mmap has some overhead, but might not be too
bad.
-Sima
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
next prev parent reply other threads:[~2024-07-30 8:56 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-07-30 7:57 [PATCH v2 0/5] Introduce DMA_HEAP_ALLOC_AND_READ_FILE heap flag Huan Yang
2024-07-30 7:57 ` [PATCH v2 1/5] dma-buf: heaps: " Huan Yang
2024-07-31 11:08 ` kernel test robot
2024-07-30 7:57 ` [PATCH v2 2/5] dma-buf: heaps: Introduce async alloc read ops Huan Yang
2024-07-30 7:57 ` [PATCH v2 3/5] dma-buf: heaps: support alloc async read file Huan Yang
2024-07-31 14:44 ` kernel test robot
2024-07-30 7:57 ` [PATCH v2 4/5] dma-buf: heaps: system_heap alloc support async read Huan Yang
2024-07-30 7:57 ` [PATCH v2 5/5] dma-buf: heaps: configurable async read gather limit Huan Yang
2024-07-30 8:03 ` [PATCH v2 0/5] Introduce DMA_HEAP_ALLOC_AND_READ_FILE heap flag Christian König
2024-07-30 8:14 ` Huan Yang
2024-07-30 8:37 ` Christian König
2024-07-30 8:46 ` Huan Yang
2024-07-30 10:43 ` Christian König
2024-07-30 11:36 ` Huan Yang
2024-07-30 13:11 ` Christian König
2024-07-31 1:48 ` Huan Yang
2024-07-30 17:19 ` T.J. Mercier
2024-07-31 1:47 ` Huan Yang
2024-07-30 8:56 ` Daniel Vetter [this message]
2024-07-30 9:05 ` Huan Yang
2024-07-30 10:42 ` Christian König
2024-07-30 11:33 ` Huan Yang
2024-07-30 12:04 ` Huan Yang
2024-07-31 20:46 ` Daniel Vetter
2024-08-01 2:53 ` Huan Yang
2024-08-05 17:53 ` Daniel Vetter
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