From: Artem Bityutskiy <dedekind@infradead.org>
To: simon polette <spolette@gmail.com>
Cc: linux-mtd@lists.infradead.org
Subject: Re: Load UBI faster
Date: Thu, 07 May 2009 08:28:12 +0300 [thread overview]
Message-ID: <1241674092.27549.16.camel@localhost.localdomain> (raw)
In-Reply-To: <1241673722.27549.14.camel@localhost.localdomain>
On Thu, 2009-05-07 at 08:22 +0300, Artem Bityutskiy wrote:
> On Wed, 2009-05-06 at 09:26 +0200, simon polette wrote:
> > I'm trying to improve boot time on a at91sam9261ek board. I boot on
> > nand flash with ubifs. It take about 400ms to load ubi and ubifs.
> > Do you know if fastboot technology, which consist in loading drivers
> > asynchronously, is conceivable with UBI ?
> > Thanks for your help.
>
> Fastbood is applicable in the situation when initialization
> is mostly about sleeping and waiting for hw. In case of UBI,
> it reads from flash and calculates CRC. The reading from NAND
> is usuall synchronous, so this process takes 100% of your CPU.
>
> One way to optimize this a little would be to use on-flash
> BBT. Usually the nand core scans full NAND to find bad blocks.
> With on-flash BBT this could be avoided. But probably this
> would not give you much.
You could also play with CRC. ATM we use CRC32 for UBI headers.
This is rather expensive if you CPU is slow. I'd try to hack
UBI and see what changes if it does not calculate it. If it
helps, you could try to consider CRC16 or adler32 instead of
CRC32.
--
Best regards,
Artem Bityutskiy (Битюцкий Артём)
next prev parent reply other threads:[~2009-05-07 5:28 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-05-06 7:26 Load UBI faster simon polette
2009-05-07 5:22 ` Artem Bityutskiy
2009-05-07 5:28 ` Artem Bityutskiy [this message]
2009-05-13 15:03 ` simon polette
2009-05-13 20:10 ` Corentin Chary
2009-05-15 12:00 ` Artem Bityutskiy
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1241674092.27549.16.camel@localhost.localdomain \
--to=dedekind@infradead.org \
--cc=linux-mtd@lists.infradead.org \
--cc=spolette@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).