[lustre-discuss] Degraded read performance with Large Bulk IO (16MB RPC)
pinkesh.valdria at oracle.com
Tue Dec 10 00:39:51 PST 2019
I was expecting better or same read performance with Large Bulk IO (16MB RPC), but I see degradation in performance. Do I need to tune any other parameter to benefit from Large Bulk IO? Appreciate if I can get any pointers to troubleshoot further.
Read: 2563 MB/s
Write: 2585 MB/s
Read: 1527 MB/s. (down by ~1025)
Write: 2859 MB/s
Changes I did are:
lctl set_param obdfilter.lfsbv-*.brw_size=16
unmounted and remounted
lctl set_param osc.lfsbv-OST*.max_pages_per_rpc=4096 (got auto-updated after re-mount)
lctl set_param osc.*.max_rpcs_in_flight=64 (Had to manually increase this to 64, since after re-mount, it was auto-set to 8, but read/write performance was poor)
lctl set_param osc.*.max_dirty_mb=2040. (setting the value to 2048 was failing with : Numerical result out of range error. Previously it was set to 2000 when I got good performance.
My other settings:
lnetctl net add --net tcp1 --if $interface –peer-timeout 180 –peer-credits 128 –credits 1024
echo "options ksocklnd nscheds=10 sock_timeout=100 credits=2560 peer_credits=63 enable_irq_affinity=0" > /etc/modprobe.d/ksocklnd.conf
lfs setstripe -c 1 -S 1M /mnt/mdt_bv/test1
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