[PATCH v2 2/2] perf help: Lower levenshtein penality for deleting character

From: Ian Rogers
Date: Fri Mar 01 2024 - 15:13:40 EST


The levenshtein penalty for deleting a character was far higher than
subsituting or inserting a character. Lower the penalty to match that
of inserting a character.

Before:
```
$ perf recccord
perf: 'recccord' is not a perf-command. See 'perf --help'.
```

After:
```
$ perf recccord
perf: 'recccord' is not a perf-command. See 'perf --help'.

Did you mean this?
record
```

Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
---
tools/perf/util/help-unknown-cmd.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/help-unknown-cmd.c b/tools/perf/util/help-unknown-cmd.c
index 2ba3369f1620..a0a46e34f8d1 100644
--- a/tools/perf/util/help-unknown-cmd.c
+++ b/tools/perf/util/help-unknown-cmd.c
@@ -73,10 +73,14 @@ const char *help_unknown_cmd(const char *cmd, struct cmdnames *main_cmds)

if (main_cmds->cnt) {
/* This reuses cmdname->len for similarity index */
- for (i = 0; i < main_cmds->cnt; ++i)
+ for (i = 0; i < main_cmds->cnt; ++i) {
main_cmds->names[i]->len =
- levenshtein(cmd, main_cmds->names[i]->name, 0, 2, 1, 4);
-
+ levenshtein(cmd, main_cmds->names[i]->name,
+ /*swap_penalty=*/0,
+ /*substition_penality=*/2,
+ /*insertion_penality=*/1,
+ /*deletion_penalty=*/1);
+ }
qsort(main_cmds->names, main_cmds->cnt,
sizeof(*main_cmds->names), levenshtein_compare);

--
2.44.0.278.ge034bb2e1d-goog