From: erik quanstrom <quanstro@quanstro.net>
To: 9fans@9fans.net
Subject: Re: [9fans] atagenioretry: nondma
Date: Sun, 19 May 2013 13:47:03 -0400 [thread overview]
Message-ID: <a50b07d4ee0c63a0fa4467d4e7f56001@ladd.quanstro.net> (raw)
In-Reply-To: <262d7c11a5d30050cdf45a4a30eab66b@gmx.de>
> i doubt this is missed interrupts. iowait() calls the interrupt handler
> itself before giving up. you can even check, as the driver keeps statistics
> about missed interrupts in the ctl file.
it can be. previously, on e.g. intel devices, we did not properly
handle dma interrupts. this lead to what appeard to be missed
interrupts. by checking for the completion condition after timeout,
this case can be eliminated from consideration. i/o is slow, but
i've done what i can to make it work as well as possible. since it's
always possible that we have new hardware with different bugs that
present the same way.
> what i would try is to check if reading the offending sectors produce
> i/o errors as well with dd.
>
> where these sectors ever written before? i dd /dev/zero over the whole
> drive before initializing filesystems on it. was something similar done
> here as well?
i didn't see which model drive this is, but this is doubtful. properly functioning
modern drives do not fail writes unless they have exhausted the
reallocation pool. being previously written should not make any difference.
9atom has smart(8), and "smart -tvp" should tell you if any drives failed.
drives with no reallocations left will exhihbit smart failure.
> could this be a prblem with the drive going into standby mode and then
> the next command taking too long to complete because drive is slow to
> spin up?
unfortunately, the ide driver doesn't have full support for PUIS.
it's not clear to me what all sata-emulating-ide firmware does in
these cases.
the (9atom) ahci driver should directly handle ALPM, PUIS and
other power-saving bits added in ahci 1.3, so i prefer to run ahci
whenever possible.
- erik
next prev parent reply other threads:[~2013-05-19 17:47 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-19 4:32 arisawa
2013-05-19 14:13 ` erik quanstrom
2013-05-19 15:55 ` cinap_lenrek
2013-05-19 17:47 ` erik quanstrom [this message]
2013-05-19 17:52 ` erik quanstrom
2013-05-20 22:10 ` arisawa
2013-05-21 1:40 ` erik quanstrom
2013-05-22 23:18 ` arisawa
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