From mboxrd@z Thu Jan  1 00:00:00 1970
From: manishrma@gmail.com (mani)
Date: Fri, 27 May 2011 17:59:38 +0530
Subject: Changes in block layer for IOScheduler Insertion selection
In-Reply-To: <BANLkTimLxWfO1hXzdROEJKx-CCMQBEXcHg@mail.gmail.com>
References: <BANLkTimLxWfO1hXzdROEJKx-CCMQBEXcHg@mail.gmail.com>
Message-ID: <BANLkTi=tn8B9S0QD_j7ky=eBydmdy9dvyA@mail.gmail.com>
To: kernelnewbies@lists.kernelnewbies.org
List-Id: kernelnewbies.lists.kernelnewbies.org

Dear All,

I am working on linux kernel 2.6.32.9 tegra NVIDIA board.

I am getting ~8MBps speed of the Nand disk if i use hdparm
hdparm -t /dev/mtdblock3

i made changes in block layer of kernel as below:-

block/blk-core.c
static inline void add_request(struct request_queue *q, struct request *req)
{
        drive_stat_acct(req, 1);

        /*
         * elevator indicated where it wants this request to be
         * inserted at elevator_merge time
         */

        __elv_add_request(q, req, ELEVATOR_INSERT_BACK, 0);
        //__elv_add_request(q, req, ELEVATOR_INSERT_SORT, 0);
}


changed ELEVATOR_INSERT_SORT to ELEVATOR_INSERT_BACK
it improves my NAND speed to 10MBps.

I am using "noop" I/O scheduler.

Will this change have any adverse effect in kernel ? or any other side
effect as far as i am using only Nand no Hard disk.


Thanks
Mani
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