[PATCH 2/4] perf tools: allow user to specify hardware breakpoint bp_len

suravee.suthikulpanit
2013-12-11T12:17:38Z

From: Jacob Shin <jacob.w.shin@gmail.com>

Currently bp_len is given a default value of 4. Allow user to override it:

$ perf stat -e mem:0x1000/8
^
bp_len

If no value is given, it will default to 4 as it did before.

Signed-off-by: Jacob Shin <jacob.w.shin@gmail.com>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
---
tools/perf/Documentation/perf-record.txt | 7 +++++--
tools/perf/util/parse-events.c | 21 +++++++++++----------
tools/perf/util/parse-events.h | 2 +-
tools/perf/util/parse-events.l | 1 +
tools/perf/util/parse-events.y | 26 ++++++++++++++++++++++++--
5 files changed, 42 insertions(+), 15 deletions(-)

diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt
index 43b42c4..7b4f594 100644
--- a/tools/perf/Documentation/perf-record.txt
+++ b/tools/perf/Documentation/perf-record.txt
@@ -33,12 +33,15 @@ OPTIONS
- a raw PMU event (eventsel+umask) in the form of rNNN where NNN is a
hexadecimal event descriptor.

- - a hardware breakpoint event in the form of '\mem:addr[:access]'
+ - a hardware breakpoint event in the form of '\mem:addr[/len][:access]'
where addr is the address in memory you want to break in.
Access is the memory access type (read, write, execute) it can
- be passed as follows: '\mem:addr[:[r][w][x]]'.
+ be passed as follows: '\mem:addr[:[r][w][x]]'. len is the range,
+ number of bytes from specified addr, which the breakpoint will cover.
If you want to profile read-write accesses in 0x1000, just set
'mem:0x1000:rw'.
+ If you want to profile write accesses in [0x1000~1008), just set
+ 'mem:0x1000/8:w'.

--filter=<filter>::
Event filter.
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 6de6f89..2a15f24 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -515,7 +515,7 @@ do { \
}

int parse_events_add_breakpoint(struct list_head *list, int *idx,
- void *ptr, char *type)
+ void *ptr, char *type, u64 len)
{
struct perf_event_attr attr;

@@ -525,14 +525,15 @@ int parse_events_add_breakpoint(struct list_head *list, int *idx,
if (parse_breakpoint_type(type, &attr))
return -EINVAL;

- /*
- * We should find a nice way to override the access length
- * Provide some defaults for now
- */
- if (attr.bp_type == HW_BREAKPOINT_X)
- attr.bp_len = sizeof(long);
- else
- attr.bp_len = HW_BREAKPOINT_LEN_4;
+ /* Provide some defaults if len is not specified */
+ if (!len) {
+ if (attr.bp_type == HW_BREAKPOINT_X)
+ len = sizeof(long);
+ else
+ len = HW_BREAKPOINT_LEN_4;
+ }
+
+ attr.bp_len = len;

attr.type = PERF_TYPE_BREAKPOINT;
attr.sample_period = 1;
@@ -1240,7 +1241,7 @@ void print_events(const char *event_glob, bool name_only)
printf("\n");

printf(" %-50s [%s]\n",
- "mem:<addr>[:access]",
+ "mem:<addr>[/len][:access]",
event_type_descriptors[PERF_TYPE_BREAKPOINT]);
printf("\n");
}
diff --git a/tools/perf/util/parse-events.h b/tools/perf/util/parse-events.h
index f1cb4c4..54a20df 100644
--- a/tools/perf/util/parse-events.h
+++ b/tools/perf/util/parse-events.h
@@ -93,7 +93,7 @@ int parse_events_add_numeric(struct list_head *list, int *idx,
int parse_events_add_cache(struct list_head *list, int *idx,
char *type, char *op_result1, char *op_result2);
int parse_events_add_breakpoint(struct list_head *list, int *idx,
- void *ptr, char *type);
+ void *ptr, char *type, u64 len);
int parse_events_add_pmu(struct list_head *list, int *idx,
char *pmu , struct list_head *head_config);
void parse_events__set_leader(char *name, struct list_head *list);
diff --git a/tools/perf/util/parse-events.l b/tools/perf/util/parse-events.l
index 3432995..199e18a 100644
--- a/tools/perf/util/parse-events.l
+++ b/tools/perf/util/parse-events.l
@@ -141,6 +141,7 @@ branch_type { return term(yyscanner, PARSE_EVENTS__TERM_TYPE_BRANCH_SAMPLE_TYPE
<mem>{
{modifier_bp} { return str(yyscanner, PE_MODIFIER_BP); }
: { return ':'; }
+"/" { return '/'; }
{num_dec} { return value(yyscanner, 10); }
{num_hex} { return value(yyscanner, 16); }
/*
diff --git a/tools/perf/util/parse-events.y b/tools/perf/util/parse-events.y
index 4eb67ec..c9adf4d 100644
--- a/tools/perf/util/parse-events.y
+++ b/tools/perf/util/parse-events.y
@@ -276,6 +276,28 @@ PE_NAME_CACHE_TYPE
}

event_legacy_mem:
+PE_PREFIX_MEM PE_VALUE '/' PE_VALUE ':' PE_MODIFIER_BP sep_dc
+{
+ struct parse_events_evlist *data = _data;
+ struct list_head *list;
+
+ ALLOC_LIST(list);
+ ABORT_ON(parse_events_add_breakpoint(list, &data->idx,
+ (void *) $2, $6, $4));
+ $$ = list;
+}
+|
+PE_PREFIX_MEM PE_VALUE '/' PE_VALUE sep_dc
+{
+ struct parse_events_evlist *data = _data;
+ struct list_head *list;
+
+ ALLOC_LIST(list);
+ ABORT_ON(parse_events_add_breakpoint(list, &data->idx,
+ (void *) $2, NULL, $4));
+ $$ = list;
+}
+|
PE_PREFIX_MEM PE_VALUE ':' PE_MODIFIER_BP sep_dc
{
struct parse_events_evlist *data = _data;
@@ -283,7 +305,7 @@ PE_PREFIX_MEM PE_VALUE ':' PE_MODIFIER_BP sep_dc

ALLOC_LIST(list);
ABORT_ON(parse_events_add_breakpoint(list, &data->idx,
- (void *) $2, $4));
+ (void *) $2, $4, 0));
$$ = list;
}
|
@@ -294,7 +316,7 @@ PE_PREFIX_MEM PE_VALUE sep_dc

ALLOC_LIST(list);
ABORT_ON(parse_events_add_breakpoint(list, &data->idx,
- (void *) $2, NULL));
+ (void *) $2, NULL, 0));
$$ = list;
}

--
1.8.1.2