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https://github.com/terassyi/bpf-batch-test
https://github.com/terassyi/bpf-batch-test
Last synced: 3 days ago
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- Host: GitHub
- URL: https://github.com/terassyi/bpf-batch-test
- Owner: terassyi
- License: mit
- Created: 2023-11-25T14:55:57.000Z (12 months ago)
- Default Branch: main
- Last Pushed: 2023-11-26T05:34:25.000Z (12 months ago)
- Last Synced: 2024-06-21T03:29:02.346Z (5 months ago)
- Language: Go
- Size: 5.86 KB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# Comparison of BPF_MAP_LOOKUP_ELEM and BPF_MAP_LOOKUP_BATCH in go
This repository compares the execution time and memory usage between `BPF_MAP_LOOKUP_ELEM` and `BPF_MAP_LOOKUP_BATCH` in golang.
I use [cilium/ebpf](https://pkg.go.dev/github.com/cilium/ebpf).
- [Map.Iterate](https://pkg.go.dev/github.com/cilium/ebpf#Map.Iterate)
- [MapIterator.Next](https://pkg.go.dev/github.com/cilium/ebpf#MapIterator.Next)
- [Map.BatchLookup](https://pkg.go.dev/github.com/cilium/ebpf#Map.BatchLookup)
## How
For test data, I define the map like below.
```c
struct
{
__uint(type, BPF_MAP_TYPE_HASH);
__uint(key_size, sizeof(u32));
__uint(value_size, sizeof(u32));
__uint(max_entries, 1024 * 1024 * 100);
} test_map SEC(".maps");
```
Before measuring, fill this map.(in [load/main.go](load/main.go))
```go
v := uint32(0xdeadbeef)
for i := 0; i < bpf.MAX_ENTRIES; i++ {
k := uint32(i)
if err := m.Update(&k, &v, ebpf.UpdateAny); err != nil {
panic(err)
}
}
```
To compare, fetch all entries of `test_map` with each way.
[normal/main.go](normal/main.go) uses `bpf_map_lookup_elem`.
```go
var k, v uint32
count := 0
iter := m.Iterate()
for iter.Next(&k, &v) {
count++
}
```
[batch/main.go](batch/main.go) uses `bpf_map_lookup_batch`.
```go
batchCount := 0
count := 0
max := m.MaxEntries()
const chunk uint32 = 4096
chSize := int(max / chunk)
kout := make([]uint32, chunk)
vout := make([]uint32, chunk)
var k uint32
var prev uint32
for i := 0; i < chSize; i++ {
c, err := m.BatchLookup(prev, &k, kout, vout, nil)
if err != nil {
panic(err)
}
count += c
batchCount++
}
```
## Result
Build sample code.
```console
$ make clean && make build
rm bpf/include/vmlinux.h
rm bin/*
rm pkg/bpf/xdpprog*
bpftool btf dump file /sys/kernel/btf/vmlinux format c > bpf/include/vmlinux.h
go generate ./...
Compiled /home/terassyi/workspace/bpf-batch-test/pkg/bpf/xdpprog_bpfeb.o
Stripped /home/terassyi/workspace/bpf-batch-test/pkg/bpf/xdpprog_bpfeb.o
Wrote /home/terassyi/workspace/bpf-batch-test/pkg/bpf/xdpprog_bpfeb.go
Compiled /home/terassyi/workspace/bpf-batch-test/pkg/bpf/xdpprog_bpfel.o
Stripped /home/terassyi/workspace/bpf-batch-test/pkg/bpf/xdpprog_bpfel.o
Wrote /home/terassyi/workspace/bpf-batch-test/pkg/bpf/xdpprog_bpfel.go
go build -o bin/batch batch/main.go
go build -o bin/normal normal/main.go
go build -o bin/load load/main.go
```
Setup test data.
```console
$ sudo bin/load
Load test program and map
map id is 668
Prepare test data...
Finish preparing test data
```
Run two programs.
(If you fail to run one program after running the other one, please stop `bin/load` and run again.)
`bpf_map_lookup_elem`
```console
$ multitime sudo bin/normal -mem
get from id: 678
Start to iterate bpf map
----- init -----
Alloc = 374176
HeapAlloc = 374176
TotalAlloc = 376120
Sys = 12254224
NumGC = 1
----- last -----
Alloc = 3614608
HeapAlloc = 3614608
TotalAlloc = 5453024352
Sys = 17497104
NumGC = 1510
------------------------
Finish iterating bpf map
Count 104857600 entries
===> multitime results
1: sudo bin/normal -mem
Mean Std.Dev. Min Median Max
real 88.923 0.000 88.923 88.923 88.923
user 0.009 0.000 0.009 0.009 0.009
sys 0.004 0.000 0.004 0.004 0.004
```
`bpf_map_lookup_batch`
```console
$ multitime sudo bin/batch -mem
get from id: 754
Start batch look up bpf map
----- init -----
Alloc = 374168
HeapAlloc = 374168
TotalAlloc = 376112
Sys = 12254224
NumGC = 1
----- last -----
Alloc = 3498736
HeapAlloc = 3498736
TotalAlloc = 840618952
Sys = 17300496
NumGC = 235
------------------------
Finish batch look up bpf map
Count 104857600 entries
Batch Count is 25600
===> multitime results
1: sudo bin/batch -mem
Mean Std.Dev. Min Median Max
real 6.973 0.000 6.973 6.973 6.973
user 0.002 0.000 0.002 0.002 0.002
sys 0.004 0.000 0.004 0.004 0.004
```