**Overview**
This PR introduces the use of
[MurmurHash3](https://en.wikipedia.org/wiki/MurmurHash) as the hashing
function for Lua's luaS_newlstr function, replacing the previous simple
hash function. The change aims to improve performance, particularly for
large strings.
**Changes**
Implemented MurmurHash3 algorithm in lstring.c
Updated luaS_newlstr to use MurmurHash3 for string hashing
**Performance Testing:**
Test Setup:
1. Ran a valkey server
2. Loaded 1000 keys with large values (100KB each) to the server using a
Lua script
```
local numKeys = 1000
for i = 1, numKeys do
local key = "large_key_" .. i
local largeValue = string.rep("x", 1024*100)
redis.call("SET", key, largeValue)
end
```
3. Used a Lua script to randomly select and retrieve keys
```
local randomKey = redis.call("RANDOMKEY")
local result = redis.call("GET", randomKey)
```
4. Benchmarked using valkey-benchmark:
`./valkey-benchmark -n 100000 evalsha
c157a37967e69569339a39a953c046fc2ecb4258 0`
Results:
A | Unstable | This PR | Change
-- | -- | -- | --
Throughput | 6,835.74 requests per second | 17,061.94 requests per
second | **+150% increase**
Avg Latency | 7.218 ms | 2.838 ms | **-61% decrease**
Min Latency | 3.144 ms | 1.320 ms | **-58% decrease**
P50 Latency | 8.463 ms | 3.167 ms | **-63% decrease**
P95 Latency | 8.863 ms | 3.527 ms | **-60% decrease**
P99 Latency | 9.063 ms | 3.663 ms | **-60% decrease**
Max Latency | 63.871 ms | 55.327 ms | **-13% decrease**
Summary:
* Throughput: Improved by 150%.
* Latency: Significant reductions in average, minimum, and percentile
latencies (P50, P95, P99), leading to much faster response times.
* Max Latency: Slightly decreased by 13%, indicating fewer outlier
delays after the fix.
---------
Signed-off-by: Shai Zarka <zarkash@amazon.com>
Signed-off-by: zarkash-aws <zarkash@amazon.com>
Signed-off-by: Madelyn Olson <madelyneolson@gmail.com>
Co-authored-by: Madelyn Olson <madelyneolson@gmail.com>
Co-authored-by: Viktor Söderqvist <viktor.soderqvist@est.tech>
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