Xen devel - Nov 2010 - oo_req, rd_req, wr_req... cant find any docs

I cannot seam to find any documentation on 
/sys/devices/vbd-<domid>-<##>/statistics/ and am trying to figure
out
what these stats represent.  From the looks of it rd_req means read 
requests.  Are these read requests that have already been completed? or 
can they be requests that are waiting/queued?

What is oo_req, all i can find on it is some comments about them being 
mysterious.

Another doc I found talks about rd_bytes but i don''t see that, i do see
rd_sect which i assume is sectors.  So is this whats meant for measuring 
how much has been transferred (assuming 512 bytes per sector)?


~ Shaun


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On 17/11/2010 19:38, "Shaun Reitan"
<mailinglists@unix-scripts.com> wrote:
> I cannot seam to find any documentation on
> /sys/devices/vbd-<domid>-<##>/statistics/ and am trying to
figure out
> what these stats represent.  From the looks of it rd_req means read
> requests.  Are these read requests that have already been completed? or
> can they be requests that are waiting/queued?
They count all requests since boot, including those for which processing has
not yet completed. Rd_req counts read requests, wr_req counts write
requests, oo_req counts the number of times that blkback paused consuming
requests because it is out of processing slots (not a massively interesting
stat to the user, probably).
> What is oo_req, all i can find on it is some comments about them being
> mysterious.
> 
> Another doc I found talks about rd_bytes but i don''t see that, i
do see
> rd_sect which i assume is sectors.  So is this whats meant for measuring
> how much has been transferred (assuming 512 bytes per sector)?
Yes an individual read/write request can span a large number of sectors.
Rd_sect/wr_sect tells you how much data has actually been transferred.

 -- Keir
> 
> ~ Shaun
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel


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