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From: "changtao381" <changtao381@163.com>
To: ceph-devel@vger.kernel.org
Subject: journal alignment
Date: Fri, 20 Nov 2015 16:33:25 +0800	[thread overview]
Message-ID: <019801d1236e$206f12e0$614d38a0$@com> (raw)

HI All,

Why it is needed an entry of journal t is aligned  by  CEPH_PAGE_MASK ?  For
it causes the data of journal write are amplified by 2X for small io

For example write io size 4096 bytes, it may write 8192 bytes

prepare_single_write 2 will write 98304 : seq 24 len 4324 -> 8192 (head 40
pre_pad 0 ebl 4324 post_pad 3788 tail 40) (ebl alignment -1)

Thanks!



             reply	other threads:[~2015-11-20  8:33 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-11-20  8:33 changtao381 [this message]
2015-11-20  8:41 ` journal alignment Haomai Wang
2015-11-20  8:42 ` Piotr.Dalek
2015-11-20  9:12   ` 答复: " changtao381
2015-11-20  9:16     ` 池信泽
2015-11-20  9:19       ` 池信泽
     [not found]     ` <alpine.DEB.2.00.1511200339470.25088@cobra.newdream.net>
2015-11-20 13:03       ` Haomai Wang
     [not found]         ` <alpine.DEB.2.00.1511200507120.24879@cobra.newdream.net>
2015-11-20 13:29           ` Haomai Wang
2015-11-20 19:53             ` Evgeniy Firsov
2015-11-23 16:59             ` Haomai Wang

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