Ming Zhang wrote:
On Fri, 2006-11-17 at 11:28 -0500, Alan D. Brunelle wrote:
Ming Zhang wrote:
Hi Alan
Thanks a lot for your quick reply. In fact I am reading your slide you
made in 04/06.
In your slide, page 20, there is a plot. For each activity, does this
high mean some activities occurred while low means no activity?
Exactly - I've found that it is sometimes better to transform the data
presented in the .dat files (in particular, sometimes there are empty
sets, and it's great for post-processing xmgrace .agr files to have all
the sets with at least something in it).
thanks. i think this plot is intuitive enough for me so far. especially
in your example, capture that hot spot is quite easy once u read from a
plot instead of from pure data line by line.
Good!
i have another question. for example, each events are marked with a
sequence number in blkparse output. but that number is not useful. i did
not ready source code yet, but i believe there is internal connection
for each event. for example, request X Q in event M, D in even N, C in
event Z... So if output of blkparse can print out such info, then we
have a complete chain to go from Q2C for each request individually.
This could be added - but in some instances there is a lot of data. Let
me take a quick look into it.
also a usage issue.
# btt -i x.blktrace.0
can show me a lot of info but blkparse show me nothing on attached
trace?
# blkparse -i x.blktrace.0
Throughput (R/W): 0KiB/s / 0KiB/s
Events (x.blktrace.0): 0 entries
Skips: 0 forward (0 - nan%)
i just check out the git tree.
you don't run btt on the raw blktrace data - you use blkparse -d <file>
to create a binary stream that btt can read.
ps, u prefer to send private email to u or always cc to list? I always
ask my list subscriber to cc lists.
Ah, switched e-mailers, I should cc the list...
Thanks!
Ming
Alan
Ming
On Fri, 2006-11-17 at 10:53 -0500, Alan D. Brunelle wrote:
Ming Zhang wrote:
Hi All
I read from a presentation that people can use xmgrace to explain the
btt results. Could anyone shed some lights on this topic? Thanks!
Ming
One of the outputs from btt is a file called <file>.dat - which contains
sets describing Q and C activity. [Basically: when IOs enter the block
IO layer, and when they are completed.] If you specify the -q or -l
options, you can get individual IO information in appropriate grace data
file format for the total time each command takes (q2c) or the time
spent in the driver and on the device (d2c).
You can import these files directly into xmgrace.
Alan
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