Messages in this thread Patch in this message | | | From | Mengting Zhang <> | Subject | [PATCH] perf parse events: Fix invalid precise_ip handling | Date | Fri, 10 Nov 2017 16:28:37 +0800 |
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When the user set a precise_ip greater than the highest precision available, perf should return EINVAL to indicate the invalid precise_ip setting.
Currently, in get_event_modifier(), perf compares the user-specified precise_ip with 3, instead of the highest precision available in the current processor. It is incorrect if the maximum precision available is less than 3.
For example, with a highest precision perf_event_attr.precise_ip = 2, the user-specified precise_ip greater than 2 should be handled as invalid argument.
Introduce perf_get_max_precise_ip() to get max precision available and compare it with the user-specified precise_ip. Also show the available max precision in an error message when the user-specified precise_ip is invalid.
Before: $./perf record -e cycles:ppp sleep 1 Error: PMU Hardware doesn't support sampling/overflow-interrupts.
After: $./perf record -e cycles:ppp sleep 1 Error: Invalid argument for precise_ip setting. The highest level of precise ip is 2 invalid or unsupported event: 'cycles:ppp' Run 'perf list' for a list of valid events
Usage: perf record [<options>] [<command>] or: perf record [<options>] -- <command> [<options>]
-e, --event <event> event selector. use 'perf list' to list available events
Signed-off-by: Mengting Zhang <zhangmengting@huawei.com> --- tools/perf/util/parse-events.c | 33 ++++++++++++++++++++++++++++++++- 1 file changed, 32 insertions(+), 1 deletion(-)
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c index 39b1596..25225f4 100644 --- a/tools/perf/util/parse-events.c +++ b/tools/perf/util/parse-events.c @@ -1369,6 +1369,32 @@ struct event_modifier { int pinned; }; +static int perf_get_max_precise_ip(void) +{ + int max_precise_ip = 0; + struct perf_event_attr attr = { + .type = PERF_TYPE_HARDWARE, + .config = PERF_COUNT_HW_CPU_CYCLES, + }; + + event_attr_init(&attr); + + attr.precise_ip = 3; + attr.sample_period = 1; + + while (attr.precise_ip != 0) { + int fd = sys_perf_event_open(&attr, 0, -1, -1, 0); + if (fd != -1){ + close(fd); + break; + } + --attr.precise_ip; + } + max_precise_ip = attr.precise_ip; + + return max_precise_ip; +} + static int get_event_modifier(struct event_modifier *mod, char *str, struct perf_evsel *evsel) { @@ -1382,6 +1408,7 @@ static int get_event_modifier(struct event_modifier *mod, char *str, int precise_max = 0; int sample_read = 0; int pinned = evsel ? evsel->attr.pinned : 0; + int max_precise_ip = 0; int exclude = eu | ek | eh; int exclude_GH = evsel ? evsel->exclude_GH : 0; @@ -1438,8 +1465,12 @@ static int get_event_modifier(struct event_modifier *mod, char *str, * * See also PERF_RECORD_MISC_EXACT_IP */ - if (precise > 3) + max_precise_ip = perf_get_max_precise_ip(); + if (precise > max_precise_ip) { + pr_err("Error: Invalid argument for precise_ip setting. \n" + "The highest level of precise ip is %d\n", max_precise_ip); return -EINVAL; + } mod->eu = eu; mod->ek = ek; -- 1.7.12.4
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