| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Date: Tue, 18 Sep 2012 07:49:05 +0200 From: Jens Axboe <axboe@...nel.dk> To: Jianpeng Ma <majianpeng@...il.com> CC: tj <tj@...nel.org>, rostedt <rostedt@...dmis.org>, fweisbec <fweisbec@...il.com>, mingo <mingo@...hat.com>, linux-kernel <linux-kernel@...r.kernel.org>, Li Zefan <lizf@...fujitsu.com>, Tao Ma <boyu.mt@...bao.com> Subject: Re: Why blktrace didn't trace requests merge? On 2012-09-18 02:30, Jianpeng Ma wrote: > On 2012-09-18 02:27 Jens Axboe <axboe@...nel.dk> Wrote: >> 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 >> > First, Thanks your time! > If i understand correctly, the merge of your example is bio with > request, not request wiht request. Yes or no? It is bio to request, correct. Request to request merges are relatively more rare. -- Jens Axboe -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists