Initial Linux ZFS GIT Repo

1 files changed, 102 insertions, 0 deletions

diff --git a/scripts/survey.sh b/scripts/survey.sh
new file mode 100755
index 000000000..9198a418f
--- /dev/null
+++ b/scripts/survey.sh
@@ -0,0 +1,102 @@
+#!/bin/bash
+
+prog=survey.sh
+. ../.script-config
+
+LOG=/home/`whoami`/zpios-logs/`uname -r`/kpios-`date +%Y%m%d`/
+mkdir -p ${LOG}
+
+# Apply all tunings described below to generate some best case
+# numbers for what is acheivable with some more elbow grease.
+NAME="prefetch+zerocopy+checksum+pending1024+kmem"
+echo "----------------------- ${NAME} ------------------------------"
+./zpios.sh                                                           \
+	""                                                           \
+	"zfs_prefetch_disable=1 zfs_vdev_max_pending=1024 zio_bulk_flags=0x100" \
+        "--zerocopy"                                                 \
+	${LOG}/${NAME}/                                              \
+        "${CMDDIR}/zfs/zfs set checksum=off lustre" |       \
+	tee ${LOG}/${NAME}.txt
+
+# Baseline number for an out of the box config with no manual tuning.
+# Ideally, we will want things to be automatically tuned and for this
+# number to approach the tweaked out results above.
+NAME="baseline"
+echo "----------------------- ${NAME} ------------------------------"
+./zpios.sh                                                           \
+	""                                                           \
+	""                                                           \
+        ""                                                           \
+	${LOG}/${NAME}/ |                                            \
+	tee ${LOG}/${NAME}.txt
+
+# Disable ZFS's prefetching.  For some reason still not clear to me
+# current prefetching policy is quite bad for a random workload.
+# Allow the algorithm to detect a random workload and not do anything
+# may be the way to address this issue.
+NAME="prefetch"
+echo "----------------------- ${NAME} ------------------------------"
+./zpios.sh                                                           \
+	""                                                           \
+	"zfs_prefetch_disable=1"                                     \
+        ""                                                           \
+	${LOG}/${NAME}/ |                                            \
+	tee ${LOG}/${NAME}.txt
+
+# As expected, simulating a zerocopy IO path improves performance
+# by freeing up lots of CPU which is wasted move data between buffers.
+NAME="zerocopy"
+echo "----------------------- ${NAME} ------------------------------"
+./zpios.sh                                                           \
+	""                                                           \
+	""                                                           \
+        "--zerocopy"                                                 \
+	${LOG}/${NAME}/ |                                            \
+	tee ${LOG}/${NAME}.txt
+
+# Disabling checksumming should show some (if small) improvement
+# simply due to freeing up a modest amount of CPU.
+NAME="checksum"
+echo "----------------------- ${NAME} ------------------------------"
+./zpios.sh                                                           \
+	""                                                           \
+	""                                                           \
+        ""                                                           \
+	${LOG}/${NAME}/                                              \
+        "${CMDDIR}/zfs/zfs set checksum=off lustre" |       \
+	tee ${LOG}/${NAME}.txt
+
+# Increasing the pending IO depth also seems to improve things likely
+# at the expense of latency.  This should be exported more because I'm
+# seeing a much bigger impact there that I would have expected.  There
+# may be some low hanging fruit to be found here.
+NAME="pending"
+echo "----------------------- ${NAME} ------------------------------"
+./zpios.sh                                                           \
+	""                                                           \
+	"zfs_vdev_max_pending=1024"                                  \
+        ""                                                           \
+	${LOG}/${NAME}/ |                                            \
+	tee ${LOG}/${NAME}.txt
+
+# To avoid memory fragmentation issues our slab implementation can be
+# based on a virtual address space.  Interestingly, we take a pretty
+# substantial performance penalty for this somewhere in the low level
+# IO drivers.  If we back the slab with kmem pages we see far better
+# read performance numbers at the cost of memory fragmention and general
+# system instability due to large allocations.  This may be because of
+# an optimization in the low level drivers due to the contigeous kmem
+# based memory.  This needs to be explained.  The good news here is that
+# with zerocopy interfaces added at the DMU layer we could gaurentee
+# kmem based memory for a pool of pages.
+#
+# 0x100 = KMC_KMEM - Force kmem_* based slab
+# 0x200 = KMC_VMEM - Force vmem_* based slab
+NAME="kmem"
+echo "----------------------- ${NAME} ------------------------------"
+./zpios.sh                                                           \
+	""                                                           \
+	"zio_bulk_flags=0x100"                                       \
+        ""                                                           \
+	${LOG}/${NAME}/ |                                            \
+	tee ${LOG}/${NAME}.txt