From: Paul Clements <Paul.Clements@SteelEye.com>
To: ptb@it.uc3m.es
Cc: neilb@cse.unsw.edu.au, linux-raid@vger.kernel.org
Subject: Re: calc. of currspeed in md.c code in 2.4.20
Date: Wed, 14 May 2003 09:48:22 -0400 [thread overview]
Message-ID: <3EC24926.1D33CAAB@SteelEye.com> (raw)
In-Reply-To: 200305140833.h4E8X5P00764@oboe.it.uc3m.es
"Peter T. Breuer" wrote:
>
> Can you shed some light on this for me?
>
> currspeed =
> (j-mddev->resync_mark_cnt)/2/((jiffies-mddev->resync_mark)/HZ +1) +1;
>
> jiffies is divided by HZ here, which results in a quantity of dimension
> time-squared!
>
> I could understand it (better) if jiffies were multiplied by HZ.
Just curious, but are you looking at this because the speed calculations
break when using a bitmap to resync? I realized this problem a few days
ago, but I'm not sure how to solve it, yet...
I think we might need two counters, one for the actual resync progress
(to display the progress bar, and show actual resync speed) and the
other to throttle I/O if actual I/O becomes too fast...
--
Paul
next prev parent reply other threads:[~2003-05-14 13:48 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-05-14 8:33 calc. of currspeed in md.c code in 2.4.20 Peter T. Breuer
2003-05-14 11:47 ` Neil Brown
2003-05-14 13:48 ` Paul Clements [this message]
2003-05-14 13:54 ` Peter T. Breuer
2003-05-14 14:18 ` Peter T. Breuer
2003-05-14 14:41 ` Paul Clements
2003-05-14 14:53 ` Peter T. Breuer
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