raw device support
sg3_utils
-
Overview
--------
(make sure the kernel module "sg" is loaded)
Raw device:
Must appear in the output of 'raw -qa'
-You may not mix raw and SCSI devices in the test specification.
+ If you need to create raw devices in order to use this tool, note that
+ raw device 0 can not be used due to a bug in certain versions of the
+ "raw" utility (including that shipped with RHEL4U4.)
+
+You may not mix raw and SCSI devices in the test specification.
Running
-------
The summary file and stdout contain lines like...
-total_size 8388608K rsz 1024 thr 1 crg 1 180.45 MB/s 1 x 180.50 = 180.50 MB/s
+dev 30 sz 125829120K rsz 1024K crg 60 thr 120 write 6036.79 [ 100.69, 106.49] read 6720.94 [ 112.64, 220.85]
-The number immediately before the first MB/s is the bandwidth computed by
-measuring total data and elapsed time. The other numbers are a check on
-the bandwidths reported by the individual sgp_dd instances.
+The number immediately after the write and the read word is the bandwidth
+in MiB/s computed by measuring total data and elapsed time. The other numbers
+are the minimal and maximal bandwidths reported by the individual sgp_dd
+instances.
If there are so many threads that sgp_dd is unlikely to be able to allocate
I/O buffers, "ENOMEM" is printed.
If not all the sgp_dd instances successfully reported a bandwidth number
"failed" is printed.
-
Visualising Results
-------------------
regions) all seem to land on top of each other, it shows the device is
phased by seeks at the given record size.
-
-The included script "parse.pl" will process output files and create
-.csv files for spreadsheet import
-
-The "plot-sgpdd.pl" script plots the results directly using gnuplot.
+The included script "iokit-plot-sgpdd" will process output files and
+create .dat (similar to csv) files for spreadsheet import. It also plots
+the results directly using gnuplot and creates .png files.