Hi Dormando, That is great insight.!. However, it did not solve the problem. I disabled turbo, as per your instructions. I even, set the CPU to operate with maximum performance, with > cpupower frequency-set --governor performance ( i verified this by monitoring cpu freq)
Still the same unexplained behavior. :(. Do you have any other suggestions? thanks --Pradeep On Mon, Oct 7, 2019 at 1:08 PM dormando <dorma...@rydia.net> wrote: > Hi, > > First as an aside; 1/1 get/set ratio is unusual for mc. The gets scale a > lot better than sets. If you get into testing more "realistic" perf > numbers make sure to increase the get rate. > > You're probably just running into CPU scaling. OS's come with a "battery > saver" or "ondemand" performance scheduler by default. They also have > turbo. Once you start loading it up more the CPU will stay in the higher > frequency states or begin to issue turbo, which will lower the latency. > > /usr/bin/echo 1 > /sys/devices/system/cpu/intel_pstate/no_turbo > cpupower frequency-set -g performance > > ... or whatever works for your platform. > > On Mon, 7 Oct 2019, Pradeep Fernando wrote: > > > Hi Devs, > > I run memaslap to understand the performance characteristics of > memcached, > > > > My setup : both memcached and memaslap running on a single machine with > NUMA. memcached is bound to NUMA 1. Gave 3GB of memory to memcached. > > workload : get/set 0.5/0.5 > > > > I increase number of thread from memaslap and observe throughput latency > numbers. > > > > I see increase in throughput (expected) but latency drops as I crease > the load. > > The initial average latency is 83 us and it drops to 30us with number of > threads = 8, this is an unexpected number.-- I expected the latency to go > up. > > Am I reading the output wrong? > > > > Apologies, if this question does not qualify for this mailing list. If > so, please direct me to correct list I can get help. :) > > > > --Pradeep > > > > > > > > Thread count = 1 > > > > > > Total Statistics (11447336 events) > > Min: 11 > > Max: 1663 > > Avg: 83 > > Geo: 79.83 > > Std: 36.39 > > Log2 Dist: > > 4: 42 594 351733 9527982 > > 8: 1551101 7451 7103 1330 > > > > cmd_get: 5723671 > > cmd_set: 5723681 > > get_misses: 0 > > written_bytes: 394933167 > > read_bytes: 343419948 > > object_bytes: 183157792 > > > > Run time: 60.0s Ops: 11447352 TPS: 190765 Net_rate: 11.7M/s > > > > Thread count = 2 > > > > Total Statistics (30888799 events) > > Min: 12 > > Max: 2011 > > Avg: 30 > > Geo: 29.68 > > Std: 15.32 > > Log2 Dist: > > 4: 170225 25862674 4766668 66398 > > 8: 154 5017 17493 170 > > > > cmd_get: 15444404 > > cmd_set: 15444411 > > get_misses: 0 > > written_bytes: 1065663678 > > read_bytes: 926663772 > > object_bytes: 494221152 > > > > Run time: 60.0s Ops: 30888815 TPS: 514751 Net_rate: 31.7M/s > > > > -- > > > > --- > > You received this message because you are subscribed to the Google > Groups "memcached" group. > > To unsubscribe from this group and stop receiving emails from it, send > an email to memcached+unsubscr...@googlegroups.com. > > To view this discussion on the web visit > https://groups.google.com/d/msgid/memcached/cd593815-c27b-4995-bb7f-21859d9a3187%40googlegroups.com > . > > > > > > -- > > --- > You received this message because you are subscribed to the Google Groups > "memcached" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to memcached+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/memcached/alpine.DEB.2.21.1910071005340.21578%40dskull > . > -- Pradeep Fernando. -- --- You received this message because you are subscribed to the Google Groups "memcached" group. To unsubscribe from this group and stop receiving emails from it, send an email to memcached+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/memcached/CAPSEm%3Dbas4jg_8ToMP3VBVE3GMfzk9vHaQ7TMXdmqUww67dFsg%40mail.gmail.com.
