This patch intends to show some benchmark results comparing a bpf
program with vs. without private stack. The patch is not intended
to land since it hacks existing kernel interface in order to
do proper comparison. The bpf program is similar to
7df4e597ea2c ("selftests/bpf: add batched, mostly in-kernel BPF triggering benchmarks")
where a raw_tp program is triggered with bpf_prog_test_run_opts() and
the raw_tp program has a loop of helper bpf_get_numa_node_id() which
will enable a fentry prog to run. The fentry prog calls three
do-nothing functions to maximumly expose the cost of private stack.
The following is the jited code for bpf prog in progs/private_stack.c
without private stack. The number of batch iterations is 4096.
subprog:
0: f3 0f 1e fa endbr64
4: 0f 1f 44 00 00 nop DWORD PTR [rax+rax*1+0x0]
9: 66 90 xchg ax,ax
b: 55 push rbp
c: 48 89 e5 mov rbp,rsp
f: f3 0f 1e fa endbr64
13: 31 c0 xor eax,eax
15: c9 leave
16: c3 ret
main prog:
0: f3 0f 1e fa endbr64
4: 0f 1f 44 00 00 nop DWORD PTR [rax+rax*1+0x0]
9: 66 90 xchg ax,ax
b: 55 push rbp
c: 48 89 e5 mov rbp,rsp
f: f3 0f 1e fa endbr64
13: 48 bf 00 e0 57 00 00 movabs rdi,0xffffc9000057e000
1a: c9 ff ff
1d: 48 8b 77 00 mov rsi,QWORD PTR [rdi+0x0]
21: 48 83 c6 01 add rsi,0x1
25: 48 89 77 00 mov QWORD PTR [rdi+0x0],rsi
29: e8 6e 00 00 00 call 0x9c
2e: e8 69 00 00 00 call 0x9c
33: e8 64 00 00 00 call 0x9c
38: 31 c0 xor eax,eax
3a: c9 leave
3b: c3 ret
The following are the jited progs with private stack:
subprog:
0: f3 0f 1e fa endbr64
4: 0f 1f 44 00 00 nop DWORD PTR [rax+rax*1+0x0]
9: 66 90 xchg ax,ax
b: 55 push rbp
c: 48 89 e5 mov rbp,rsp
f: f3 0f 1e fa endbr64
13: 49 b9 70 a6 c1 08 7e movabs r9,0x607e08c1a670
1a: 60 00 00
1d: 65 4c 03 0c 25 00 1a add r9,QWORD PTR gs:0x21a00
24: 02 00
26: 31 c0 xor eax,eax
28: c9 leave
29: c3 ret
main prog:
0: f3 0f 1e fa endbr64
4: 0f 1f 44 00 00 nop DWORD PTR [rax+rax*1+0x0]
9: 66 90 xchg ax,ax
b: 55 push rbp
c: 48 89 e5 mov rbp,rsp
f: f3 0f 1e fa endbr64
13: 49 b9 88 a6 c1 08 7e movabs r9,0x607e08c1a688
1a: 60 00 00
1d: 65 4c 03 0c 25 00 1a add r9,QWORD PTR gs:0x21a00
24: 02 00
26: 48 bf 00 d0 5b 00 00 movabs rdi,0xffffc900005bd000
2d: c9 ff ff
30: 48 8b 77 00 mov rsi,QWORD PTR [rdi+0x0]
34: 48 83 c6 01 add rsi,0x1
38: 48 89 77 00 mov QWORD PTR [rdi+0x0],rsi
3c: 41 51 push r9
3e: e8 46 23 51 e1 call 0xffffffffe1512389
43: 41 59 pop r9
45: 41 51 push r9
47: e8 3d 23 51 e1 call 0xffffffffe1512389
4c: 41 59 pop r9
4e: 41 51 push r9
50: e8 34 23 51 e1 call 0xffffffffe1512389
55: 41 59 pop r9
57: 31 c0 xor eax,eax
59: c9 leave
5a: c3 ret
