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Add ability to compare and contrast two veristat runs, previously
recorded with veristat using CSV output format.
When veristat is called with -C (--compare) flag, veristat expects
exactly two input files specified, both should be in CSV format.
Expectation is that it's output from previous veristat runs, but as long
as column names and formats match, it should just work. First CSV file
is designated as a "baseline" provided, and the second one is
comparison (experiment) data set. Establishing baseline matters later
when calculating difference percentages, see below.
Veristat parses these two CSV files and "reconstructs" verifier stats
(it could be just a subset of all possible stats). File and program
names are mandatory as they are used as joining key (these two "stats"
are designated as "key stats" in the code).
Veristat currently enforces that the set of stats recorded in both CSV
has to exactly match, down to exact order. This is just a simplifying
condition which can be lifted with a bit of additional pre-processing to
reorded stat specs internally, which I didn't bother doing, yet.
For all the non-key stats, veristat will output three columns: one for
baseline data, one for comparison data, and one with an absolute and
relative percentage difference. If either baseline or comparison values
are missing (that is, respective CSV file doesn't have a row with
*exactly* matching file and program name), those values are assumed to
be empty or zero. In such case relative percentages are forced to +100%
or -100% output, for consistency with a typical case.
Veristat's -e (--emit) and -s (--sort) specs still apply, so even if CSV
contains lots of stats, user can request to compare only a subset of
them (and specify desired column order as well). Similarly, both CSV and
human-readable table output is honored. Note that input is currently
always expected to be CSV.
Here's an example shell session, recording data for biosnoop tool on two
different kernels and comparing them afterwards, outputting data in table
format.
# on slightly older production kernel
$ sudo ./veristat biosnoop_bpf.o
File Program Verdict Duration (us) Total insns Total states Peak states
-------------- ------------------------ ------- ------------- ----------- ------------ -----------
biosnoop_bpf.o blk_account_io_merge_bio success 37 24 1 1
biosnoop_bpf.o blk_account_io_start failure 0 0 0 0
biosnoop_bpf.o block_rq_complete success 76 104 6 6
biosnoop_bpf.o block_rq_insert success 83 85 7 7
biosnoop_bpf.o block_rq_issue success 79 85 7 7
-------------- ------------------------ ------- ------------- ----------- ------------ -----------
Done. Processed 1 object files, 5 programs.
$ sudo ./veristat ~/local/tmp/fbcode-bpf-objs/biosnoop_bpf.o -o csv > baseline.csv
$ cat baseline.csv
file_name,prog_name,verdict,duration,total_insns,total_states,peak_states
biosnoop_bpf.o,blk_account_io_merge_bio,success,36,24,1,1
biosnoop_bpf.o,blk_account_io_start,failure,0,0,0,0
biosnoop_bpf.o,block_rq_complete,success,82,104,6,6
biosnoop_bpf.o,block_rq_insert,success,78,85,7,7
biosnoop_bpf.o,block_rq_issue,success,74,85,7,7
# on latest bpf-next kernel
$ sudo ./veristat biosnoop_bpf.o
File Program Verdict Duration (us) Total insns Total states Peak states
-------------- ------------------------ ------- ------------- ----------- ------------ -----------
biosnoop_bpf.o blk_account_io_merge_bio success 31 24 1 1
biosnoop_bpf.o blk_account_io_start failure 0 0 0 0
biosnoop_bpf.o block_rq_complete success 76 104 6 6
biosnoop_bpf.o block_rq_insert success 83 91 7 7
biosnoop_bpf.o block_rq_issue success 74 91 7 7
-------------- ------------------------ ------- ------------- ----------- ------------ -----------
Done. Processed 1 object files, 5 programs.
$ sudo ./veristat biosnoop_bpf.o -o csv > comparison.csv
$ cat comparison.csv
file_name,prog_name,verdict,duration,total_insns,total_states,peak_states
biosnoop_bpf.o,blk_account_io_merge_bio,success,71,24,1,1
biosnoop_bpf.o,blk_account_io_start,failure,0,0,0,0
biosnoop_bpf.o,block_rq_complete,success,82,104,6,6
biosnoop_bpf.o,block_rq_insert,success,83,91,7,7
biosnoop_bpf.o,block_rq_issue,success,87,91,7,7
# now let's compare with human-readable output (note that no sudo needed)
# we also ignore verification duration in this case to shortned output
$ ./veristat -C baseline.csv comparison.csv -e file,prog,verdict,insns
File Program Verdict (A) Verdict (B) Verdict (DIFF) Total insns (A) Total insns (B) Total insns (DIFF)
-------------- ------------------------ ----------- ----------- -------------- --------------- --------------- ------------------
biosnoop_bpf.o blk_account_io_merge_bio success success MATCH 24 24 +0 (+0.00%)
biosnoop_bpf.o blk_account_io_start failure failure MATCH 0 0 +0 (+100.00%)
biosnoop_bpf.o block_rq_complete success success MATCH 104 104 +0 (+0.00%)
biosnoop_bpf.o block_rq_insert success success MATCH 91 85 -6 (-6.59%)
biosnoop_bpf.o block_rq_issue success success MATCH 91 85 -6 (-6.59%)
-------------- ------------------------ ----------- ----------- -------------- --------------- --------------- ------------------
While not particularly exciting example (it turned out to be kind of hard to
quickly find a nice example with significant difference just because of kernel
version bump), it should demonstrate main features.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20220921164254.3630690-4-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Add a small tool, veristat, that allows mass-verification of
a set of *libbpf-compatible* BPF ELF object files. For each such object
file, veristat will attempt to verify each BPF program *individually*.
Regardless of success or failure, it parses BPF verifier stats and
outputs them in human-readable table format. In the future we can also
add CSV and JSON output for more scriptable post-processing, if necessary.
veristat allows to specify a set of stats that should be output and
ordering between multiple objects and files (e.g., so that one can
easily order by total instructions processed, instead of default file
name, prog name, verdict, total instructions order).
This tool should be useful for validating various BPF verifier changes
or even validating different kernel versions for regressions.
Here's an example for some of the heaviest selftests/bpf BPF object
files:
$ sudo ./veristat -s insns,file,prog {pyperf,loop,test_verif_scale,strobemeta,test_cls_redirect,profiler}*.linked3.o
File Program Verdict Duration, us Total insns Total states Peak states
------------------------------------ ------------------------------------ ------- ------------ ----------- ------------ -----------
loop3.linked3.o while_true failure 350990 1000001 9663 9663
test_verif_scale3.linked3.o balancer_ingress success 115244 845499 8636 2141
test_verif_scale2.linked3.o balancer_ingress success 77688 773445 3048 788
pyperf600.linked3.o on_event success 2079872 624585 30335 30241
pyperf600_nounroll.linked3.o on_event success 353972 568128 37101 2115
strobemeta.linked3.o on_event success 455230 557149 15915 13537
test_verif_scale1.linked3.o balancer_ingress success 89880 554754 8636 2141
strobemeta_nounroll2.linked3.o on_event success 433906 501725 17087 1912
loop6.linked3.o trace_virtqueue_add_sgs success 282205 398057 8717 919
loop1.linked3.o nested_loops success 125630 361349 5504 5504
pyperf180.linked3.o on_event success 2511740 160398 11470 11446
pyperf100.linked3.o on_event success 744329 87681 6213 6191
test_cls_redirect.linked3.o cls_redirect success 54087 78925 4782 903
strobemeta_subprogs.linked3.o on_event success 57898 65420 1954 403
test_cls_redirect_subprogs.linked3.o cls_redirect success 54522 64965 4619 958
strobemeta_nounroll1.linked3.o on_event success 43313 57240 1757 382
pyperf50.linked3.o on_event success 194355 46378 3263 3241
profiler2.linked3.o tracepoint__syscalls__sys_enter_kill success 23869 43372 1423 542
pyperf_subprogs.linked3.o on_event success 29179 36358 2499 2499
profiler1.linked3.o tracepoint__syscalls__sys_enter_kill success 13052 27036 1946 936
profiler3.linked3.o tracepoint__syscalls__sys_enter_kill success 21023 26016 2186 915
profiler2.linked3.o kprobe__vfs_link success 5255 13896 303 271
profiler1.linked3.o kprobe__vfs_link success 7792 12687 1042 1041
profiler3.linked3.o kprobe__vfs_link success 7332 10601 865 865
profiler2.linked3.o kprobe_ret__do_filp_open success 3417 8900 216 199
profiler2.linked3.o kprobe__vfs_symlink success 3548 8775 203 186
pyperf_global.linked3.o on_event success 10007 7563 520 520
profiler3.linked3.o kprobe_ret__do_filp_open success 4708 6464 532 532
profiler1.linked3.o kprobe_ret__do_filp_open success 3090 6445 508 508
profiler3.linked3.o kprobe__vfs_symlink success 4477 6358 521 521
profiler1.linked3.o kprobe__vfs_symlink success 3381 6347 507 507
profiler2.linked3.o raw_tracepoint__sched_process_exec success 2464 5874 292 189
profiler3.linked3.o raw_tracepoint__sched_process_exec success 2677 4363 397 283
profiler2.linked3.o kprobe__proc_sys_write success 1800 4355 143 138
profiler1.linked3.o raw_tracepoint__sched_process_exec success 1649 4019 333 240
pyperf600_bpf_loop.linked3.o on_event success 2711 3966 306 306
profiler2.linked3.o raw_tracepoint__sched_process_exit success 1234 3138 83 66
profiler3.linked3.o kprobe__proc_sys_write success 1755 2623 223 223
profiler1.linked3.o kprobe__proc_sys_write success 1222 2456 193 193
loop2.linked3.o while_true success 608 1783 57 30
profiler3.linked3.o raw_tracepoint__sched_process_exit success 789 1680 146 146
profiler1.linked3.o raw_tracepoint__sched_process_exit success 592 1526 133 133
strobemeta_bpf_loop.linked3.o on_event success 1015 1512 106 106
loop4.linked3.o combinations success 165 524 18 17
profiler3.linked3.o raw_tracepoint__sched_process_fork success 196 299 25 25
profiler1.linked3.o raw_tracepoint__sched_process_fork success 109 265 19 19
profiler2.linked3.o raw_tracepoint__sched_process_fork success 111 265 19 19
loop5.linked3.o while_true success 47 84 9 9
------------------------------------ ------------------------------------ ------- ------------ ----------- ------------ -----------
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220909193053.577111-4-andrii@kernel.org
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