Hi list
I have a test environment with following,
A memcached (memcached -d -m 50000 -u root -p 12301 -c 1000000 -t 16) in cpu cgroup with following config,
cpu.cfs_quota_us = 400000
cpu.cfs_period_us = 100000
And a mutilate loop (mutilate -s x.x.x.x:12301 -T 40 -c 20 -t 60 -W 5 -q 1000000) running on another host
w/o any cgroup config,
When bind memcached to 0-15 with cpuset,
==========================================
mutilate showed,
#type avg std min 5th 10th 90th 95th 99th
read 1275.8 6358.9 49.8 378.2 418.5 767.2 841.4 53998.5
update 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
op_q 1.0 0.0 1.0 1.0 1.0 1.1 1.1 1.1
Total QPS = 626566.2 (37594133 / 60.0s)
Misses = 0 (0.0%)
Skipped TXs = 0 (0.0%)
RX 9288150851 bytes : 147.6 MB/s
TX 1353390552 bytes : 21.5 MB/s
And perf on memcached showed,
635,602,955,852 cycles (30.07%)
479,554,401,177 instructions # 0.75 insn per cycle (40.02%)
12,585,059,799 L1-dcache-load-misses # 9.31% of all L1-dcache hits (50.07%)
135,140,424,785 L1-dcache-loads (49.96%)
76,849,156,759 L1-dcache-stores (50.02%)
45,700,267,543 L1-icache-load-misses (49.97%)
495,149,862 LLC-load-misses # 24.96% of all LL-cache hits (39.95%)
1,984,134,589 LLC-loads (39.97%)
327,130,920 LLC-store-misses (20.06%)
1,397,111,117 LLC-stores (20.06%)
When bind memcached to 0-3 with cpuset,
========================================
mutilate showed,
#type avg std min 5th 10th 90th 95th 99th
read 934.7 3669.3 41.1 112.8 129.5 385.3 3321.9 21923.7
update 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
op_q 1.0 0.0 1.0 1.0 1.0 1.1 1.1 1.1
Total QPS = 852885.6 (51173140 / 60.0s)
Misses = 0 (0.0%)
Skipped TXs = 0 (0.0%)
RX 12642165580 bytes : 200.9 MB/s
TX 1842259932 bytes : 29.3 MB/s
And perf on memcached showed,
621,311,916,151 cycles (30.01%)
599,835,965,997 instructions # 0.97 insn per cycle (40.02%)
12,585,889,988 L1-dcache-load-misses # 7.59% of all L1-dcache hits (50.00%)
165,750,518,361 L1-dcache-loads (50.01%)
93,588,611,989 L1-dcache-stores (50.00%)
44,445,213,037 L1-icache-load-misses (50.01%)
568,410,466 LLC-load-misses # 26.91% of all LL-cache hits (40.03%)
2,112,218,392 LLC-loads (40.00%)
261,202,604 LLC-store-misses (19.97%)
1,484,886,714 LLC-stores
We can see the IPC raised from 0.75 to 0.97, this should be the reason of the performance boost.
What does cause the IPC boost ?
Thanks a million for any help
Jianchao
