https://bugzilla.kernel.org/show_bug.cgi?id=71641 --- Comment #3 from Chia-Hung Chang <fredchang.tc@xxxxxxxxx> --- Test command : dd if=/dev/zero of=/share/CACHEDEV2_DATA/orderno5G bs=1M count=5120 The results of block trace can be download as follow. https://dl.dropboxusercontent.com/u/32959539/blktrace_original_data.7z The results of btt can be download as follow. https://dl.dropboxusercontent.com/u/32959539/blktrace_output.7z There are three folders: /journal -->ext4,data=journal with 375MB/s /order_delalloc -->ext4,data=ordered,delalloc with 937MB/s /order_nodelalloc -->ext4,data=ordered,nodelalloc with 353MB/s The size of write request with data=ordered,delalloc is 64k mostly. The size of write requests with data=journal and data=ordered,nodelalloc are 4k mostly. If we observe the average Q2Q in btt results, which means time interval between requests, we have /journal 0.00081 /order_nodelalloc 0.00031 It seems to be the reason of performance degradation. Is any one know why the time interval of requests is significantly longer with data=journal? -- You are receiving this mail because: You are watching the assignee of the bug. -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
