On 2012-09-17 19:55, Tejun Heo wrote: > (cc'ing Jens) > > On Mon, Sep 17, 2012 at 09:22:28AM -0400, Steven Rostedt wrote: >> On Mon, 2012-09-17 at 19:33 +0800, Jianpeng Ma wrote: >>> Hi all: >>> I used blktrace to trace some io.But i can't find requests merge. I >>> searched the code and did't not find. >>> Why? >>> >> >> No idea. I don't use blktrace much, but I Cc'd those that understand it >> better than I.
Works for me: [...] 8,0 0 26 0.009147735 664 A WS 315226143 + 8 <- (8,7) 19406344 8,0 0 27 0.009148677 664 Q WS 315226143 + 8 [btrfs-submit-1] 8,0 0 28 0.009152967 664 G WS 315226143 + 8 [btrfs-submit-1] 8,0 0 29 0.009154242 664 P N [btrfs-submit-1] 8,0 0 30 0.009155538 664 A WS 315226151 + 8 <- (8,7) 19406352 8,0 0 31 0.009155743 664 Q WS 315226151 + 8 [btrfs-submit-1] 8,0 0 32 0.009157086 664 M WS 315226151 + 8 [btrfs-submit-1] 8,0 0 33 0.009158716 664 I WS 315226143 + 16 [btrfs-submit-1] That's from a quick trace of /dev/sda. I started blktrace, then did: $ dd if=/dev/zero of=foo bs=4k count=128 && sync to ensure that I knew merges would be happening. Output stats at the end: Total (sda): Reads Queued: 7, 44KiB Writes Queued: 447, 7692KiB Read Dispatches: 7, 44KiB Write Dispatches: 416, 7692KiB Reads Requeued: 0 Writes Requeued: 0 Reads Completed: 7, 44KiB Writes Completed: 435, 5864KiB Read Merges: 0, 0KiB Write Merges: 23, 428KiB IO unplugs: 78 Timer unplugs: 0 -- Jens Axboe -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
