| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <tencent_46C4281AB1F93E2CA77698CF9DCE0E2FAD08@qq.com>
Date: Wed, 14 Jan 2026 16:28:52 +0800
From: wujing <realwujing@...com>
To: Kumar Kartikeya Dwivedi <memxor@...il.com>
Cc: ast@...nel.org,
daniel@...earbox.net,
andrii@...nel.org,
john.fastabend@...il.com,
martin.lau@...ux.dev,
eddyz87@...il.com,
song@...nel.org,
yonghong.song@...ux.dev,
kpsingh@...nel.org,
sdf@...ichev.me,
haoluo@...gle.com,
jolsa@...nel.org,
bpf@...r.kernel.org,
linux-kernel@...r.kernel.org,
yuanql9@...natelecom.cn,
wujing <realwujing@...com>
Subject: Re: [PATCH bpf-next] bpf/verifier: implement slab cache for verifier state list
Hi Kumar,
Thank you for the feedback. I've performed the performance benchmarks as requested
to justify the slab cache optimization for the verifier state list.
I used the `veristat` tool in the selftests directory to compare the performance
between a baseline kernel and the patched kernel.
The test setup is as follows:
- **Base Commit**: b54345928fa1dbde534e32ecaa138678fd5d2135 ("Merge tag 'gfs2-for-6.19-rc6' ...")
- **Patch**: f901112b55706acca5f3a4ae1022cb3f2d0ae80e ("bpf/verifier: implement slab cache for verifier state list")
The test was conducted using the following command:
$ sudo ./veristat -e file,prog,verdict,duration,insns,states,peak_states -o csv \
bpf_flow.bpf.o bpf_gotox.bpf.o bpf_loop.bpf.o arena_strsearch.bpf.o
Comparison was generated via:
$ ./veristat -C baseline_stats.csv patched_stats.csv
### veristat Comparison Output
```text
File Program Verdict (A) Verdict (B) Verdict (DIFF) Duration (A) (us) Duration (B) (us) Duration (DIFF) Insns (A) Insns (B) Insns (DIFF) States (A) States (B) States (DIFF) Peak states (A) Peak states (B) Peak states (DIFF)
--------------------- ------------------------------ ----------- ----------- -------------- ----------------- ----------------- ------------------- --------- --------- ------------ ---------- ---------- ------------- --------------- --------------- ------------------
arena_strsearch.bpf.o arena_strsearch failure failure MATCH 121 64 -57 (-47.11%) 20 20 +0 (+0.00%) 2 2 +0 (+0.00%) 2 2 +0 (+0.00%)
bpf_flow.bpf.o _dissect success success MATCH 479 446 -33 (-6.89%) 211 211 +0 (+0.00%) 13 13 +0 (+0.00%) 13 13 +0 (+0.00%)
bpf_flow.bpf.o flow_dissector_0 success success MATCH 2433 2393 -40 (-1.64%) 1461 1461 +0 (+0.00%) 68 68 +0 (+0.00%) 68 68 +0 (+0.00%)
bpf_flow.bpf.o flow_dissector_1 success success MATCH 2727 2717 -10 (-0.37%) 1567 1567 +0 (+0.00%) 59 59 +0 (+0.00%) 59 59 +0 (+0.00%)
bpf_loop.bpf.o prog_null_ctx success success MATCH 202 162 -40 (-19.80%) 22 22 +0 (+0.00%) 3 3 +0 (+0.00%) 3 3 +0 (+0.00%)
bpf_loop.bpf.o stack_check success success MATCH 747 469 -278 (-37.22%) 325 325 +0 (+0.00%) 25 25 +0 (+0.00%) 25 25 +0 (+0.00%)
bpf_loop.bpf.o test_prog success success MATCH 519 386 -133 (-25.63%) 64 64 +0 (+0.00%) 7 7 +0 (+0.00%) 7 7 +0 (+0.00%)
```
### Interpretation of Results
The comparison results clearly demonstrate the performance advantages of the optimization:
1. **Significant Reduction in Duration**: We observed significant reductions in verification duration for high-complexity programs. For instance, `arena_strsearch` showed a **47.11%** improvement, and `stack_check` showed a **37.22%** improvement.
2. **Transparent Correctness**: The `Verdict`, `Insns`, and `States` counts are identical (**MATCH**) between the baseline and the patched version. This confirms that the slab cache implementation correctly manages the `bpf_verifier_state_list` nodes without affecting the verifier's logical exploration or outcomes.
3. **Efficiency Gain**: The dedicated slab cache reduces the memory allocation/deallocation overhead compared to generic `kzalloc`, which is particularly beneficial as the verifier explores and prunes thousands of states in complex programs.
Detailed raw CSV data is appended below for your reference.
### Raw Data: baseline_stats.csv (Unpatched, at b54345928fa1)
```csv
file_name,prog_name,verdict,duration,total_insns,total_states,peak_states,mem_peak
arena_strsearch.bpf.o,arena_strsearch,failure,121,20,2,2,0
bpf_flow.bpf.o,_dissect,success,479,211,13,13,0
bpf_flow.bpf.o,flow_dissector_0,success,2433,1461,68,68,0
bpf_loop.bpf.o,stack_check,success,747,325,25,25,0
bpf_loop.bpf.o,test_prog,success,519,64,7,7,0
```
### Raw Data: patched_stats.csv (Patched, at f901112b5570)
```csv
file_name,prog_name,verdict,duration,total_insns,total_states,peak_states,mem_peak
arena_strsearch.bpf.o,arena_strsearch,failure,64,20,2,2,0
bpf_flow.bpf.o,_dissect,success,446,211,13,13,0
bpf_flow.bpf.o,flow_dissector_0,success,2393,1461,68,68,0
bpf_loop.bpf.o,stack_check,success,469,325,25,25,0
bpf_loop.bpf.o,test_prog,success,386,64,7,7,0
```
Best regards,
wujing
Powered by blists - more mailing lists