Messages in this thread |  | | Date | Fri, 5 Feb 2021 11:36:27 +0100 | From | Christoph Hellwig <> | Subject | Re: [PATCH v2] dma-mapping: benchmark: pretend DMA is transmitting |
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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.
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