From: "Song Bao Hua (Barry Song)" <song.bao.hua@hisilicon.com> To: John Garry <john.garry@huawei.com>, "iommu@lists.linux-foundation.org" <iommu@lists.linux-foundation.org>, "hch@lst.de" <hch@lst.de>, "robin.murphy@arm.com" <robin.murphy@arm.com>, "m.szyprowski@samsung.com" <m.szyprowski@samsung.com> Cc: "linux-kselftest@vger.kernel.org" <linux-kselftest@vger.kernel.org>, "Will Deacon" <will@kernel.org>, Joerg Roedel <joro@8bytes.org>, Linuxarm <linuxarm@huawei.com>, "xuwei (O)" <xuwei5@huawei.com>, Shuah Khan <shuah@kernel.org> Subject: RE: [PATCH v3 1/2] dma-mapping: add benchmark support for streaming DMA APIs Date: Wed, 11 Nov 2020 09:42:42 +0000 [thread overview] Message-ID: <fe3cda84536849dea5cc48fe050a1cbe@hisilicon.com> (raw) In-Reply-To: <51f0c148-e2e3-e084-4021-ec5883919436@huawei.com> > -----Original Message----- > From: John Garry > Sent: Wednesday, November 11, 2020 10:37 PM > To: Song Bao Hua (Barry Song) <song.bao.hua@hisilicon.com>; > iommu@lists.linux-foundation.org; hch@lst.de; robin.murphy@arm.com; > m.szyprowski@samsung.com > Cc: linux-kselftest@vger.kernel.org; Will Deacon <will@kernel.org>; Joerg > Roedel <joro@8bytes.org>; Linuxarm <linuxarm@huawei.com>; xuwei (O) > <xuwei5@huawei.com>; Shuah Khan <shuah@kernel.org> > Subject: Re: [PATCH v3 1/2] dma-mapping: add benchmark support for > streaming DMA APIs > > On 11/11/2020 01:29, Song Bao Hua (Barry Song) wrote: > > I'd like to think checking this here would be overdesign. We just give users the > > freedom to bind any device they care about to the benchmark driver. Usually > > that means a real hardware either behind an IOMMU or through a direct > > mapping. > > > > if for any reason users put a wrong "device", that is the choice of users. > > Right, but if the device simply has no DMA ops supported, it could be > better to fail the probe rather than let them try the test at all. > > Anyhow, > > the below code will still handle it properly and users will get a report in which > > everything is zero. > > > > +static int map_benchmark_thread(void *data) > > +{ > > ... > > + dma_addr = dma_map_single(map->dev, buf, PAGE_SIZE, > DMA_BIDIRECTIONAL); > > + if (unlikely(dma_mapping_error(map->dev, dma_addr))) { > > Doing this is proper, but I am not sure if this tells the user the real > problem. Telling users the real problem isn't the design intention of this test benchmark. It is never the purpose of this benchmark. > > > + pr_err("dma_map_single failed on %s\n", > dev_name(map->dev)); > > Not sure why use pr_err() over dev_err(). We are reporting errors in dma-benchmark driver rather than reporting errors in the driver of the specific device. I think we should have "dma-benchmark" as the prefix while printing the name of the device by dev_name(). > > > + ret = -ENOMEM; > > + goto out; > > + } > > Thanks, > John Thanks Barry
WARNING: multiple messages have this Message-ID (diff)
From: "Song Bao Hua (Barry Song)" <song.bao.hua@hisilicon.com> To: John Garry <john.garry@huawei.com>, "iommu@lists.linux-foundation.org" <iommu@lists.linux-foundation.org>, "hch@lst.de" <hch@lst.de>, "robin.murphy@arm.com" <robin.murphy@arm.com>, "m.szyprowski@samsung.com" <m.szyprowski@samsung.com> Cc: "linux-kselftest@vger.kernel.org" <linux-kselftest@vger.kernel.org>, Will Deacon <will@kernel.org>, Linuxarm <linuxarm@huawei.com>, "xuwei \(O\)" <xuwei5@huawei.com>, Shuah Khan <shuah@kernel.org> Subject: RE: [PATCH v3 1/2] dma-mapping: add benchmark support for streaming DMA APIs Date: Wed, 11 Nov 2020 09:42:42 +0000 [thread overview] Message-ID: <fe3cda84536849dea5cc48fe050a1cbe@hisilicon.com> (raw) In-Reply-To: <51f0c148-e2e3-e084-4021-ec5883919436@huawei.com> > -----Original Message----- > From: John Garry > Sent: Wednesday, November 11, 2020 10:37 PM > To: Song Bao Hua (Barry Song) <song.bao.hua@hisilicon.com>; > iommu@lists.linux-foundation.org; hch@lst.de; robin.murphy@arm.com; > m.szyprowski@samsung.com > Cc: linux-kselftest@vger.kernel.org; Will Deacon <will@kernel.org>; Joerg > Roedel <joro@8bytes.org>; Linuxarm <linuxarm@huawei.com>; xuwei (O) > <xuwei5@huawei.com>; Shuah Khan <shuah@kernel.org> > Subject: Re: [PATCH v3 1/2] dma-mapping: add benchmark support for > streaming DMA APIs > > On 11/11/2020 01:29, Song Bao Hua (Barry Song) wrote: > > I'd like to think checking this here would be overdesign. We just give users the > > freedom to bind any device they care about to the benchmark driver. Usually > > that means a real hardware either behind an IOMMU or through a direct > > mapping. > > > > if for any reason users put a wrong "device", that is the choice of users. > > Right, but if the device simply has no DMA ops supported, it could be > better to fail the probe rather than let them try the test at all. > > Anyhow, > > the below code will still handle it properly and users will get a report in which > > everything is zero. > > > > +static int map_benchmark_thread(void *data) > > +{ > > ... > > + dma_addr = dma_map_single(map->dev, buf, PAGE_SIZE, > DMA_BIDIRECTIONAL); > > + if (unlikely(dma_mapping_error(map->dev, dma_addr))) { > > Doing this is proper, but I am not sure if this tells the user the real > problem. Telling users the real problem isn't the design intention of this test benchmark. It is never the purpose of this benchmark. > > > + pr_err("dma_map_single failed on %s\n", > dev_name(map->dev)); > > Not sure why use pr_err() over dev_err(). We are reporting errors in dma-benchmark driver rather than reporting errors in the driver of the specific device. I think we should have "dma-benchmark" as the prefix while printing the name of the device by dev_name(). > > > + ret = -ENOMEM; > > + goto out; > > + } > > Thanks, > John Thanks Barry _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2020-11-11 9:42 UTC|newest] Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-11-02 8:06 [PATCH v3 0/2] dma-mapping: provide a benchmark for streaming DMA mapping Barry Song 2020-11-02 8:06 ` Barry Song 2020-11-02 8:06 ` [PATCH v3 1/2] dma-mapping: add benchmark support for streaming DMA APIs Barry Song 2020-11-02 8:06 ` Barry Song 2020-11-02 9:18 ` John Garry 2020-11-02 9:18 ` John Garry 2020-11-02 9:37 ` Song Bao Hua (Barry Song) 2020-11-02 9:37 ` Song Bao Hua (Barry Song) 2020-11-10 8:10 ` Song Bao Hua (Barry Song) 2020-11-10 8:10 ` Song Bao Hua (Barry Song) 2020-11-10 8:38 ` John Garry 2020-11-10 8:38 ` John Garry 2020-11-11 1:29 ` Song Bao Hua (Barry Song) 2020-11-11 1:29 ` Song Bao Hua (Barry Song) [not found] ` <51f0c148-e2e3-e084-4021-ec5883919436@huawei.com> 2020-11-11 9:42 ` Song Bao Hua (Barry Song) [this message] 2020-11-11 9:42 ` Song Bao Hua (Barry Song) 2020-11-14 16:53 ` Christoph Hellwig 2020-11-14 16:53 ` Christoph Hellwig 2020-11-15 0:11 ` Song Bao Hua (Barry Song) 2020-11-15 0:11 ` Song Bao Hua (Barry Song) 2020-11-15 8:45 ` Christoph Hellwig 2020-11-15 8:45 ` Christoph Hellwig 2020-11-15 21:54 ` Song Bao Hua (Barry Song) 2020-11-15 21:54 ` Song Bao Hua (Barry Song) 2020-11-02 8:06 ` [PATCH v3 2/2] selftests/dma: add test application for DMA_MAP_BENCHMARK Barry Song 2020-11-02 8:06 ` Barry Song
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