Changes in block layer for IOScheduler Insertion selection

From: manishrma@gmail.com (mani)
To: kernelnewbies@lists.kernelnewbies.org
Subject: Changes in block layer for IOScheduler Insertion selection
Date: Thu, 2 Jun 2011 09:11:35 +0530	[thread overview]
Message-ID: <BANLkTinbMfmF1m_vA6RiP5Y-dnOueyOKwg@mail.gmail.com> (raw)
In-Reply-To: <BANLkTikiupHHuAQd-z0dBBRzhrb5=49TqA@mail.gmail.com>

Dear All,

Any suggestions on the below point ?

Thanks in advance..

On Mon, May 30, 2011 at 10:53 AM, mani <manishrma@gmail.com> wrote:

> Dear Eduardo,
>
>    I am using squashfs filesystem. So i am more concern with the read
> speed.
>     whereas below are the details
>                                                      read speed   write
> speed
>     ELEVATOR_INSERT_SORT       8 MBps            5MBps
>     ELEVATOR_INSERT_BACK      10 MBps           7.2MBps
>
>    used the following command for measurement for both the cases.
>    reading
>    hdparm -t /dev/mtdblock3
>
>    writing
>    dd if=/dev/zero of=/dev/mtd3 bs=4096 count=100k
>
>    As of now everything is working fine with those changes
>    but i am worried if these changes would have any adverse effect anywhere
> ?
>
>    Thanks.
>
>
> On Fri, May 27, 2011 at 8:37 PM, Eduardo Silva <edsiper@gmail.com> wrote:
>
>> On Fri, May 27, 2011 at 8:29 AM, mani <manishrma@gmail.com> wrote:
>> >
>> > 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);
>> > }
>> >
>> >
>>
>> What are the results for read and write for both cases ?
>>
>>
>> > 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
>> >
>> >
>> > _______________________________________________
>> > Kernelnewbies mailing list
>> > Kernelnewbies at kernelnewbies.org
>> > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>> >
>> >
>>
>>
>>
>> --
>> Eduardo Silva
>> http://edsiper.linuxchile.cl
>> http://www.monkey-project.com
>>
>
>
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