UMEM-CACHE-BENCHMARK

UMEM-CACHE-BENCHMARK is a benchmark project for user space in memory cache.

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RANDOM SIZE BENCHMARK

We limit server memory to MEM_LIMIT, and test case size is set to 4 times of that, and the size of key and value is random in the range[0, KV_LIMIT]. We first get the value from the server, if the get missed, we store it. And 80% of the time the first 20% of the test cases are used.

FIXED SIZE BENCHMARK

We limit server memory to MEM_LIMIT, and test case size is set to 4 times of that, and the size of key and value is KV_LIMIT. We first get the value from the server, if the get missed, we store it. And 80% of the time the first 20% of the test cases are used.

SUPPORTED APPS

• Memcached
• UmemCache
• Pogocache
• Redis1
• Redis2
• Redis3
• Redis4

Note: because Redis is designed to be single-threaded, it may not be able to fully utilize the performance of the test machine, so we support it running multiple instances and distributing keys evenly across these instances.

Note: we use APP's default port

TEST COMMAND

RANDOM-2G-1M

make test-{APP}-random-2g-1m REMOTE_IP=[::1]

RANDOM-100M-1K

make test-{APP}-random-100m-1k REMOTE_IP=[::1]

2G-513K

make test-{APP}-2g-513k REMOTE_IP=[::1]

100M-512B

make test-{APP}-100m-512b REMOTE_IP=[::1]

TEST RESULT

We discovered a serious issue with memcached in our benchmark test, there is a corner case that your set of a key will never succeed. Specifically, if you exhausted slab's storage space with chunk data allocated by big keys before storing any keys into it, you'll unable to store keys that meet the slab's items size. It can be reproduced by following commands:

# bash A

./memcached --conn-limit=512 --memory-limit=100 --max-item-size=1048576 -t 4 -u root

# bash B

a_540k=$(for i in {1..552960}; do printf "a"; done)
a_20000=$(for i in {1..20000}; do printf "a"; done)
a_30000=$(for i in {1..30000}; do printf "a"; done)

for i in {1..180}; do
        printf "set ${i} 0 0 552960\r\n${a_540k}\r\n" | nc 127.0.0.1 11211
done

for i in {201..344}; do
        printf "set ${i} 0 0 20000\r\n${a_20000}\r\n" | nc 127.0.0.1 11211
done

# this set can never be stored
printf "set 400 0 0 30000\r\n${a_30000}\r\n" | nc 127.0.0.1 11211

RPI4B

Two 4GB version of Raspberry Pi 4 Model B connected in LAN with Gigabit network. One used as a server and the other as a client. And the installed operating system is Fedora-Server-40-1.14.aarch64.

Test result is at rpi4b .