* Cleaned up sgpdd-survey

*  Added a README for sgpdd-survey

diff --git a/lustre-iokit/sgpdd-survey/README b/lustre-iokit/sgpdd-survey/README
new file mode 100644 (file)
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+++ b/lustre-iokit/sgpdd-survey/README
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+
+Requirements
+------------
+
+. sg3_utils (for sgp_dd)
+. SCSI device
+
+
+Overview
+--------
+
+This survey may be used to characterise the performance of a SCSI device.
+It simulates an OST serving multiple stripe files.  The data gathered by it
+can help set expectations for the performance of a lustre OST exporting the
+device.
+
+The script uses sgp_dd to do raw sequential disk I/O.  It runs with
+variable numbers of sgp_dd threads to show how performance varies with
+different request queue depths.
+
+The script spawns variable numbers of sgp_dd instances, each reading or
+writing a separate area of the disk to show how performance varies with the
+number of concurrent stripe files.
+
+
+Running
+-------
+
+The script must be customised according to the particular device under test
+and where it should keep its working files.   Customisation variables are
+described clearly at the start of the script.
+
+When the script runs, it creates a number of working files and a pair of
+result files.  All files start with the prefix given by ${rslt}.
+
+${rslt}_<date/time>.summary    same as stdout
+${rslt}_<date/time>_*          tmp files
+${rslt}_<date/time>.detail     collected tmp files for post-mortem
+
+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
+
+The first number 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.
+
+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
+-------------------
+
+I've found it most useful to import the summary data (it's fixed width)
+into Excel (or any graphing package) and graph bandwidth v. # threads for
+varying numbers of concurrent regions.  This shows how the device performs
+with varying queue depth.  If the series (varying numbers of concurrent
+regions) all seem to land on top of each other, it shows the device is
+phased by seeks at the given record size.
+

diff --git a/lustre-iokit/sgpdd-survey/sgpdd-survey b/lustre-iokit/sgpdd-survey/sgpdd-survey
new file mode 100755 (executable)
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+#!/bin/bash
+
+######################################################################
+# customize per survey
+
+# the SG device to measure
+dev=/dev/sg6
+
+# result file prefix
+# NB ensure the path exists if it includes subdirs
+rslt=/tmp/sg_dd_rslt
+
+# what to do (read or write)
+action=write
+
+# total size (MBytes)
+# NB bigger than device cache is good
+size=8192
+
+# record size (KBytes)
+rszlo=1024
+rszhi=1024
+
+# Concurrent regions
+crglo=1
+crghi=4
+
+# total numbers of threads to share between concurrent regions
+# NB survey skips over #thr < #regions
+thrlo=1
+thrhi=1024
+
+#####################################################################
+
+# disk block size (Bytes)
+bs=512
+
+if [ $action = read ]; then
+    f1="if=$dev"
+    f2="of=/dev/null"
+    skip=skip
+else
+    f1="if=/dev/zero"
+    f2="of=$dev"
+    skip=seek
+fi
+
+start=`date +%F@%R`
+rsltf=${rslt}_${start}.summary
+echo -n > $rsltf
+workf=${rslt}_${start}.detail
+echo -n > $workf
+
+print_summary () {
+    if [ "$1" = "-n" ]; then
+       minusn=$1; shift
+    else
+       minusn=""
+    fi
+    echo $minusn "$*" >> $rsltf
+    echo $minusn "$*"
+}
+
+for ((rsz=$rszlo;rsz<=$rszhi;rsz*=2)); do
+    for ((crg=$crglo;crg<=$crghi;crg*=2)); do 
+       for ((thr=$thrlo;thr<=$thrhi;thr*=2)); do
+           if ((thr < crg)); then
+               continue
+           fi
+           # compute parameters
+           bpt=$((rsz*1024/bs))
+           blocks=$((size*((1024*1024)/bs)/crg))
+           count=$blocks
+           # show computed parameters
+           actual_rsz=$((bpt*bs/1024))
+           actual_size=$((bs*count*crg/1024))
+           str=`printf 'total_size %8dK rsz %4d thr %5d crg %3d ' \
+                        $actual_size $actual_rsz $thr $crg`
+           echo "==============> $str" >> $workf
+           print_summary -n "$str"
+           freemem=`awk < /proc/meminfo '/^MemTotal:/ {printf "%d\n", $2}'`
+           if (((actual_rsz * thr /crg + 64) * crg > freemem)); then
+               print_summary "ENOMEM"
+               continue
+           fi
+           # start test
+           t0=`date +%s.%N`
+           for ((i=0;i<crg;i++)); do 
+               sgp_dd 2> ${rslt}_tmp${i} \
+                   $f1 $f2 ${skip}=$((1024+i*blocks)) \
+                   thr=$((thr/crg)) count=$count bs=$bs bpt=$bpt time=1&
+           done 
+           wait
+           t1=`date +%s.%N`
+           # collect all results in 1 file
+           rfile=${rslt}_thr${thr}_crg${crg}_rsz${rsz}
+           echo > $rfile
+           ok=0
+           for ((i=0;i<crg;i++)); do
+               rtmp=${rslt}_tmp${i}
+               if grep 'time to transfer data' $rtmp > /dev/null 2>&1; then
+                   ok=$((ok + 1))
+               fi
+               cat ${rslt}_tmp${i} >> $rfile
+               cat ${rslt}_tmp${i} >> $workf
+               rm ${rslt}_tmp${i}
+           done
+           if [ $ok -ne $crg ]; then
+               print_summary `printf "failed %d" $((crg - ok))`
+           else
+               # compute MB/sec from elapsed
+               bw=`awk "BEGIN {printf \"%6.2f MB/s\", $actual_size / (( $t1 - $t0 ) * 1024); exit}"`
+               # compute MB/sec from nregions*slowest
+               check=`awk < $rfile \
+                          '/time to transfer data/ {mb=$8/1.048576; if (n == 0 || mb < min) min = mb; n++}\
+                           END {printf "%3d x %6.2f = %6.2f MB/s", n, min, min * n}'`
+                print_summary "$bw $check"
+           fi
+           rm $rfile
+       done
+    done
+done