[Linux] blktrace related
Event type of blktrace - A : remap - Q: IO is queued - G: a request struct allocated (get request) - P: the queue is plugged - I: the IO is scheduled - U: the queue is unplugged - D: the IO is dispatched to the device - C: the IO is completed (C) Source code in Linux kernel - location: kernel/trace/blktrace.c - blk_fill_rwbs ( ) : set F, W, D, R, N, A, S, M, E flag - blktrace.c 파일에 register_block_xx(blk_add_trace_xx, NULL) 함수로 등록하고 외부에서 사용할때는 block/blk-core.c 파일에서 trace_block_xx(q, rq) 함수로 block layer를 tracing한다. Link for explaining blktrace - http://brooker.co.za/blog/2013/07/14/io-performance.html - http://studyfoss.egloos.com/tag/blktrace/page/1 -