| Message ID | 1472573965-3881-6-git-send-email-mathieu.poirier@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
On 31 August 2016 at 03:37, Suzuki K Poulose <Suzuki.Poulose@arm.com> wrote: > On 30/08/16 17:19, Mathieu Poirier wrote: >> >> Using the PMU::set_drv_config() callback to enable the CoreSight >> sink that will be used for the trace session. > > >> +int cs_etm_set_drv_config(struct perf_evsel_config_term *term) >> +{ >> + int ret; >> + char enable_sink[ENABLE_SINK_MAX]; >> + >> + snprintf(enable_sink, ENABLE_SINK_MAX, "%s/%s", >> + term->val.drv_cfg, "enable_sink"); >> + >> + ret = cs_device__print_file(enable_sink, "%d", 1); >> + if (ret < 0) >> + return ret; >> + >> + return 0; >> +} > > > > Don't we have to disable the sink at the end of the session ? How is that > taken care of ? Did I miss that ? > Correct - the sink has to be disabled once it is no longer needed. It is a little tricky to do and I haven't decided on the best way to proceed. Fortunately that aspect doesn't affect this patchset. Mathieu > Suzuki
On 1 September 2016 at 03:04, Suzuki K Poulose <Suzuki.Poulose@arm.com> wrote: > On 31/08/16 15:14, Mathieu Poirier wrote: >> >> On 31 August 2016 at 03:37, Suzuki K Poulose <Suzuki.Poulose@arm.com> >> wrote: >>> >>> On 30/08/16 17:19, Mathieu Poirier wrote: >>>> >>>> >>>> Using the PMU::set_drv_config() callback to enable the CoreSight >>>> sink that will be used for the trace session. >>> >>> >>> >>>> +int cs_etm_set_drv_config(struct perf_evsel_config_term *term) >>>> +{ >>>> + int ret; >>>> + char enable_sink[ENABLE_SINK_MAX]; >>>> + >>>> + snprintf(enable_sink, ENABLE_SINK_MAX, "%s/%s", >>>> + term->val.drv_cfg, "enable_sink"); >>>> + >>>> + ret = cs_device__print_file(enable_sink, "%d", 1); >>>> + if (ret < 0) >>>> + return ret; >>>> + >>>> + return 0; >>>> +} >>> >>> >>> >>> >>> Don't we have to disable the sink at the end of the session ? How is that >>> taken care of ? Did I miss that ? >>> >> >> Correct - the sink has to be disabled once it is no longer needed. It >> is a little tricky to do and I haven't decided on the best way to >> proceed. Fortunately that aspect doesn't affect this patchset. > > > Well, this patchset when used, could leave a sink enabled. At this time it does yes, but that is a problem inherent to the CoreSight framework rather than perf's ability to push driver specific configuration to the PMU drivers. That is the reason why I decided to address this issue in a later patch. There is also the fact that I haven't heard back from Arnaldo on this approach - if I get asked to proceed differently then the method for disabling sinks will have to change. > If we a choose > a different sink (say an ETF) from the perf, which occurs before the > previous sink (say an ETR) in the coresight path, the perf wouldn't get any > trace data, without any clue. > > May be we could register an atexit() handler for clearing the sink ? So that > it is guaranteed to clear it irrespective of the path taken by perf to exit > ? Yes, that would be the most intuitive solution but it won't work for CoreSight. The PMU driver allows multiple traces session to exist concurrently and that, with different sinks for each session (if the HW topology supports it). As such the sink for a session needs to be disabled at driver level as soon as it got recognised in the configuration of a path. That way the next session, which may start before the previous one ended, doesn't trip on the sink that was selected earlier. I thought about a solution and I think it can work but before moving ahead with it, I need to have an idea of how this patchset will go. Thanks for the comments, Mathieu > > Cheers > Suzuki >
diff --git a/tools/perf/arch/arm/util/cs-etm.c b/tools/perf/arch/arm/util/cs-etm.c index 829c479614f1..dfea6b635525 100644 --- a/tools/perf/arch/arm/util/cs-etm.c +++ b/tools/perf/arch/arm/util/cs-etm.c @@ -27,12 +27,16 @@ #include "../../util/auxtrace.h" #include "../../util/cpumap.h" #include "../../util/evlist.h" +#include "../../util/evsel.h" #include "../../util/pmu.h" #include "../../util/thread_map.h" #include "../../util/cs-etm.h" #include <stdlib.h> +#define ENABLE_SINK_MAX 128 +#define CS_BUS_DEVICE_PATH "/bus/coresight/devices/" + struct cs_etm_recording { struct auxtrace_record itr; struct perf_pmu *cs_etm_pmu; @@ -557,3 +561,55 @@ struct auxtrace_record *cs_etm_record_init(int *err) out: return NULL; } + +static FILE *cs_device__open_file(const char *name) +{ + struct stat st; + char path[PATH_MAX]; + const char *sysfs; + + sysfs = sysfs__mountpoint(); + if (!sysfs) + return NULL; + + snprintf(path, PATH_MAX, + "%s" CS_BUS_DEVICE_PATH "%s", sysfs, name); + + if (stat(path, &st) < 0) + return NULL; + + return fopen(path, "w"); + +} + +static __attribute__((format(printf, 2, 3))) +int cs_device__print_file(const char *name, const char *fmt, ...) +{ + va_list args; + FILE *file; + int ret = -EINVAL; + + va_start(args, fmt); + file = cs_device__open_file(name); + if (file) { + ret = vfprintf(file, fmt, args); + fclose(file); + } + va_end(args); + return ret; +} + +int cs_etm_set_drv_config(struct perf_evsel_config_term *term) +{ + int ret; + char enable_sink[ENABLE_SINK_MAX]; + + snprintf(enable_sink, ENABLE_SINK_MAX, "%s/%s", + term->val.drv_cfg, "enable_sink"); + + ret = cs_device__print_file(enable_sink, "%d", 1); + if (ret < 0) + return ret; + + return 0; +} diff --git a/tools/perf/arch/arm/util/cs-etm.h b/tools/perf/arch/arm/util/cs-etm.h index 909f486d02d1..5256741be549 100644 --- a/tools/perf/arch/arm/util/cs-etm.h +++ b/tools/perf/arch/arm/util/cs-etm.h @@ -18,6 +18,9 @@ #ifndef INCLUDE__PERF_CS_ETM_H__ #define INCLUDE__PERF_CS_ETM_H__ +#include "../../util/evsel.h" + struct auxtrace_record *cs_etm_record_init(int *err); +int cs_etm_set_drv_config(struct perf_evsel_config_term *term); #endif diff --git a/tools/perf/arch/arm/util/pmu.c b/tools/perf/arch/arm/util/pmu.c index af9fb666b44f..c11f8a13d14d 100644 --- a/tools/perf/arch/arm/util/pmu.c +++ b/tools/perf/arch/arm/util/pmu.c @@ -19,8 +19,10 @@ #include <linux/coresight-pmu.h> #include <linux/perf_event.h> +#include "cs-etm.h" #include "../../util/pmu.h" + struct perf_event_attr *perf_pmu__get_default_config(struct perf_pmu *pmu __maybe_unused) { @@ -28,6 +30,7 @@ struct perf_event_attr if (!strcmp(pmu->name, CORESIGHT_ETM_PMU_NAME)) { /* add ETM default config here */ pmu->selectable = true; + pmu->set_drv_config = cs_etm_set_drv_config; } #endif return NULL;