kvm/powerpc: memcached benchmark

Yu Zhao
2023-06-09T01:00:07Z

TLDR
====
Memcached achieved 10% more operations per second (in ~4 hours) after this patchset [1].

Hardware
========
HOST $ lscpu
Architecture: ppc64le
Byte Order: Little Endian
CPU(s): 184
On-line CPU(s) list: 0-183
Model name: POWER9 (raw), altivec supported
Model: 2.2 (pvr 004e 1202)
Thread(s) per core: 4
Core(s) per socket: 23
Socket(s): 2
CPU max MHz: 3000.0000
CPU min MHz: 2300.0000
Caches (sum of all):
L1d: 1.4 MiB (46 instances)
L1i: 1.4 MiB (46 instances)
L2: 12 MiB (24 instances)
L3: 240 MiB (24 instances)
NUMA:
NUMA node(s): 2
NUMA node0 CPU(s): 0-91
NUMA node1 CPU(s): 92-183
Vulnerabilities:
Itlb multihit: Not affected
L1tf: Mitigation; RFI Flush, L1D private per thread
Mds: Not affected
Meltdown: Mitigation; RFI Flush, L1D private per thread
Mmio stale data: Not affected
Retbleed: Not affected
Spec store bypass: Mitigation; Kernel entry/exit barrier (eieio)
Spectre v1: Mitigation; __user pointer sanitization, ori31 speculation barrier enabled
Spectre v2: Mitigation; Indirect branch serialisation (kernel only), Indirect branch cache disabled, Software link stack flush
Srbds: Not affected
Tsx async abort: Not affected

HOST $ numactl -H
available: 2 nodes (0-1)
node 0 cpus: 0-91
node 0 size: 261659 MB
node 0 free: 259152 MB
node 1 cpus: 92-183
node 1 size: 261713 MB
node 1 free: 261076 MB
node distances:
node 0 1
0: 10 40
1: 40 10

HOST $ cat /sys/class/nvme/nvme0/model
INTEL SSDPF21Q800GB

HOST $ cat /sys/class/nvme/nvme0/numa_node
0

Software
========
HOST $ cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=22.04
DISTRIB_CODENAME=jammy
DISTRIB_DESCRIPTION="Ubuntu 22.04 LTS"

HOST $ uname -a
Linux ppc 6.3.0 #1 SMP Sun Jun 4 18:26:37 UTC 2023 ppc64le ppc64le ppc64le GNU/Linux

HOST $ cat /proc/swaps
Filename Type Size Used Priority
/dev/nvme0n1p2 partition 466838272 0 -2

HOST $ cat /sys/kernel/mm/lru_gen/enabled
0x0009

HOST $ cat /sys/kernel/mm/transparent_hugepage/enabled
always madvise [never]

HOST $ cat /sys/kernel/mm/transparent_hugepage/defrag
always defer defer+madvise madvise [never]

HOST $ qemu-system-ppc64 --version
QEMU emulator version 6.2.0 (Debian 1:6.2+dfsg-2ubuntu6.6)
Copyright (c) 2003-2021 Fabrice Bellard and the QEMU Project developers

GUEST $ cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=22.04
DISTRIB_CODENAME=jammy
DISTRIB_DESCRIPTION="Ubuntu 22.04.1 LTS"

GUEST $ cat /etc/memcached.conf
...
-t 92
-m 262144
-B binary
-s /var/run/memcached/memcached.sock
-a 0766

GUEST $ memtier_benchmark -v
memtier_benchmark 1.4.0
Copyright (C) 2011-2022 Redis Ltd.
This is free software. You may redistribute copies of it under the terms of
the GNU General Public License <http://www.gnu.org/licenses/gpl.html>.
There is NO WARRANTY, to the extent permitted by law.

Procedure
=========
HOST $ sudo numactl -N 0 -m 0 qemu-system-ppc64 \
-M pseries,accel=kvm,kvm-type=HV -cpu host -smp 92 -m 270g
-nographic -nic user \
-drive if=virtio,format=raw,file=/dev/nvme0n1p1

GUEST $ memtier_benchmark -S /var/run/memcached/memcached.sock \
-P memcache_binary -c 1 -t 92 --pipeline 1 --ratio 1:0 \
--key-minimum=1 --key-maximum=120000000 --key-pattern=P:P \
-n allkeys -d 2000

GUEST $ memtier_benchmark -S /var/run/memcached/memcached.sock \
-P memcache_binary -c 1 -t 92 --pipeline 1 --ratio 0:1 \
--key-minimum=1 --key-maximum=120000000 --key-pattern=R:R \
-n allkeys --randomize --distinct-client-seed

Results
=======
Before [1] After Change
-------------------------------------------------
Ops/sec 721586.10 800210.12 +10%
Avg. Latency 0.12546 0.11260 -10%
p50 Latency 0.08700 0.08700 N/C
p99 Latency 0.28700 0.24700 -13%

Notes
=====
[1] "mm: rmap: Don't flush TLB after checking PTE young for page
reference" was included so that the comparison is apples to
Apples.