From: Christoph Hellwig <hch@lst.de>
To: "Song Bao Hua (Barry Song)" <song.bao.hua@hisilicon.com>
Cc: Christoph Hellwig <hch@lst.de>,
"m.szyprowski@samsung.com" <m.szyprowski@samsung.com>,
"robin.murphy@arm.com" <robin.murphy@arm.com>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linuxarm@openeuler.org" <linuxarm@openeuler.org>
Subject: Re: [PATCH v2] dma-mapping: benchmark: pretend DMA is transmitting
Date: Fri, 5 Feb 2021 11:36:27 +0100 [thread overview]
Message-ID: <20210205103627.GB6694@lst.de> (raw)
In-Reply-To: <e4c784d93cdd41d285bdddb650fb9471@hisilicon.com>
On Fri, Feb 05, 2021 at 10:32:26AM +0000, Song Bao Hua (Barry Song) wrote:
> I can keep the struct size unchanged by changing the struct to
>
> struct map_benchmark {
> __u64 avg_map_100ns; /* average map latency in 100ns */
> __u64 map_stddev; /* standard deviation of map latency */
> __u64 avg_unmap_100ns; /* as above */
> __u64 unmap_stddev;
> __u32 threads; /* how many threads will do map/unmap in parallel */
> __u32 seconds; /* how long the test will last */
> __s32 node; /* which numa node this benchmark will run on */
> __u32 dma_bits; /* DMA addressing capability */
> __u32 dma_dir; /* DMA data direction */
> __u32 dma_trans_ns; /* time for DMA transmission in ns */
>
> __u32 exp; /* For future use */
> __u64 expansion[9]; /* For future use */
> };
>
> But the code is really ugly now.
Thats why we usually use __u8 fields for reserved field. You might
consider just switching to that instead while you're at it. I guess
we'll just have to get the addition into 5.11 then to make sure we
don't release a kernel with the alignment fix.
next prev parent reply other threads:[~2021-02-05 10:40 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-05 2:00 [PATCH v2] dma-mapping: benchmark: pretend DMA is transmitting Barry Song
2021-02-05 9:21 ` Christoph Hellwig
2021-02-05 10:32 ` Song Bao Hua (Barry Song)
2021-02-05 10:36 ` Christoph Hellwig [this message]
2021-02-05 10:52 ` Song Bao Hua (Barry Song)
2021-02-05 10:56 ` Christoph Hellwig
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