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Diffstat (limited to 'scripts/survey.sh')
| -rwxr-xr-x | scripts/survey.sh | 102 |
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 |