Re: Determining disk activity per volume
Re: Determining disk activity per volume
- Subject: Re: Determining disk activity per volume
- From: Thulli <email@hidden>
- Date: Sat, 7 Oct 2006 07:14:03 +0800
>> determining when read or write functions are called. However,
this polling approach doesn't strike me as very elegant.
Option 1. If you are interested only in read and write system calls
and don't want to do polling, take a look at this.
http://developer.apple.com/technotes/tn2005/tn2127.html. You need to
write a kauth hook and user land client process. If the kauth hook
kext could provide a device interface, then the user land client can
block on a "read(/dev/yourKauthDevice)" and process what you read
with no polling.
Option 2. If you don't want to write a kext and still achieve results
with NO polling, then take a look at this
http://developer.apple.com/documentation/Performance/Conceptual/
FileSystem/Articles/TrackingChanges.html
thanks,
Thulli.
On 06-Oct-06, at 10:02 AM, Rick Mann wrote:
Hi. I'd like to implement a disk activity indicator that lives in
the menu bar. I'm looking for suggestions on how to determine when
a particular a volume, device, or the filesystem (in decreasing
order of desirability) is reading from or writing to a device.
I have these requirements:
a) Do not destabilize the OS
b) Low system overhead
c) Reasonably rapid update (> 10 fps)
I've been looking at the fs_usage sources and sysctl() using
KERN_KDREADTR, and determining when read or write functions are
called. However, this polling approach doesn't strike me as very
elegant. I suppose I could make the call 10 times each second, and
then process the results, but it seems very unwieldy to do this. I
also don't know much about KERN_KDREADTR, because I can't seem to
find any documentation about it.
8
I'm trying to find the sources for sysctl(), but I don't know where
to look (is there a way to look up the location of commands and
functions?).
I'd appreciate any suggestions. Thanks!
--
Rick
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