On Sun, 26 May 2013 16:58:59 +0800, ethan said:
> Fred£¬
> How do you know the disk is completely idle ?
Actually, my first question was "How do you know the disk is *spinning*?"
A second or two delay sounds suspiciously like a spun-down disk in powersave
move
pgpsOF7D6aAkH.pgp
On Sun, 26 May 2013 16:58:59 +0800, ethan said:
Fred£¬
How do you know the disk is completely idle ?
Actually, my first question was How do you know the disk is *spinning*?
A second or two delay sounds suspiciously like a spun-down disk in powersave
move
pgpsOF7D6aAkH.pgp
Am 26.05.2013 07:29, schrieb Fredrik Tolf:
> I'm sure you all know what the various fields are (except the first,
Hmm, I had to look at Documentation/block/stat.txt.
> which is just a timestamp), so as you can see, there are 135 requests in
> the queue, but no reads or writes happen, in this
Fred，
How do you know the disk is completely idle ? How much cache memory do
your controller and disk have ? Why do you think the requests should trigger
action of disk immediately while you don't know what kind of requests are they.
They are reading the same offset of the same block ?
Dear list,
In order to debug I/O performance, I recently wrote a tiny program for
inspecting /sys/block/$DISK/stat. It works by dumping deltas of the values
every 100 ms, quite simply (except the queue-length value, for which
deltas are clearly useless).
Using this, I often see periods
Dear list,
In order to debug I/O performance, I recently wrote a tiny program for
inspecting /sys/block/$DISK/stat. It works by dumping deltas of the values
every 100 ms, quite simply (except the queue-length value, for which
deltas are clearly useless).
Using this, I often see periods
Fred，
How do you know the disk is completely idle ? How much cache memory do
your controller and disk have ? Why do you think the requests should trigger
action of disk immediately while you don't know what kind of requests are they.
They are reading the same offset of the same block ?
Am 26.05.2013 07:29, schrieb Fredrik Tolf:
I'm sure you all know what the various fields are (except the first,
Hmm, I had to look at Documentation/block/stat.txt.
which is just a timestamp), so as you can see, there are 135 requests in
the queue, but no reads or writes happen, in this case,
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