In order to support usersapce access, an event must be mmapped. While there's already mmap support for evlist, the usecase is a bit different than the self monitoring with userspace access. So let's add a new perf_evsel__mmap() function to mmap an evsel. This allows implementing userspace access as a fastpath for perf_evsel__read().
The mmapped address is returned by perf_evsel__mmap_base() which primarily for users/tests to check if userspace access is enabled. Signed-off-by: Rob Herring <[email protected]> --- v5: - Create an mmap for every underlying event opened. Due to this, we need a different way to get the mmap ptr, so perf_evsel__mmap_base() is introduced. v4: - Change perf_evsel__mmap size to pages instead of bytes v3: - New patch split out from user access patch --- tools/lib/perf/Documentation/libperf.txt | 2 + tools/lib/perf/evsel.c | 47 +++++++++++++++++++++++- tools/lib/perf/include/internal/evsel.h | 2 + tools/lib/perf/include/perf/evsel.h | 2 + tools/lib/perf/libperf.map | 2 + 5 files changed, 53 insertions(+), 2 deletions(-) diff --git a/tools/lib/perf/Documentation/libperf.txt b/tools/lib/perf/Documentation/libperf.txt index 0c74c30ed23a..a2c73df191ca 100644 --- a/tools/lib/perf/Documentation/libperf.txt +++ b/tools/lib/perf/Documentation/libperf.txt @@ -136,6 +136,8 @@ SYNOPSIS struct perf_thread_map *threads); void perf_evsel__close(struct perf_evsel *evsel); void perf_evsel__close_cpu(struct perf_evsel *evsel, int cpu); + int perf_evsel__mmap(struct perf_evsel *evsel, int pages); + void *perf_evsel__mmap_base(struct perf_evsel *evsel, int cpu, int thread); int perf_evsel__read(struct perf_evsel *evsel, int cpu, int thread, struct perf_counts_values *count); int perf_evsel__enable(struct perf_evsel *evsel); diff --git a/tools/lib/perf/evsel.c b/tools/lib/perf/evsel.c index 4dc06289f4c7..0b5bdf4badae 100644 --- a/tools/lib/perf/evsel.c +++ b/tools/lib/perf/evsel.c @@ -11,10 +11,12 @@ #include <stdlib.h> #include <internal/xyarray.h> #include <internal/cpumap.h> +#include <internal/mmap.h> #include <internal/threadmap.h> #include <internal/lib.h> #include <linux/string.h> #include <sys/ioctl.h> +#include <sys/mman.h> void perf_evsel__init(struct perf_evsel *evsel, struct perf_event_attr *attr) { @@ -37,11 +39,17 @@ void perf_evsel__delete(struct perf_evsel *evsel) free(evsel); } -#define FD(e, x, y) (*(int *) xyarray__entry(e->fd, x, y)) +struct evsel_fd { + int fd; + struct perf_mmap mmap; +}; + +#define FD(e, x, y) ((struct evsel_fd *) xyarray__entry(e->fd, x, y))->fd +#define MMAP(e, x, y) (&(((struct evsel_fd *) xyarray__entry(e->fd, x, y))->mmap)) int perf_evsel__alloc_fd(struct perf_evsel *evsel, int ncpus, int nthreads) { - evsel->fd = xyarray__new(ncpus, nthreads, sizeof(int)); + evsel->fd = xyarray__new(ncpus, nthreads, sizeof(struct evsel_fd)); if (evsel->fd) { int cpu, thread; @@ -156,6 +164,41 @@ void perf_evsel__close_cpu(struct perf_evsel *evsel, int cpu) perf_evsel__close_fd_cpu(evsel, cpu); } +int perf_evsel__mmap(struct perf_evsel *evsel, int pages) +{ + int ret, cpu, thread; + struct perf_mmap_param mp = { + .prot = PROT_READ | PROT_WRITE, + .mask = (pages * page_size) - 1, + }; + + for (cpu = 0; cpu < xyarray__max_x(evsel->fd); cpu++) { + for (thread = 0; thread < xyarray__max_y(evsel->fd); thread++) { + int fd = FD(evsel, cpu, thread); + struct perf_mmap *map = MMAP(evsel, cpu, thread); + + if (fd < 0) + continue; + + perf_mmap__init(map, NULL, false, NULL); + + ret = perf_mmap__mmap(map, &mp, fd, cpu); + if (ret) + return -1; + } + } + + return 0; +} + +void *perf_evsel__mmap_base(struct perf_evsel *evsel, int cpu, int thread) +{ + if (FD(evsel, cpu, thread) < 0) + return NULL; + + return MMAP(evsel, cpu, thread)->base; +} + int perf_evsel__read_size(struct perf_evsel *evsel) { u64 read_format = evsel->attr.read_format; diff --git a/tools/lib/perf/include/internal/evsel.h b/tools/lib/perf/include/internal/evsel.h index 1ffd083b235e..a7985dbb68ff 100644 --- a/tools/lib/perf/include/internal/evsel.h +++ b/tools/lib/perf/include/internal/evsel.h @@ -9,6 +9,7 @@ struct perf_cpu_map; struct perf_thread_map; +struct perf_mmap; struct xyarray; /* @@ -40,6 +41,7 @@ struct perf_evsel { struct perf_cpu_map *cpus; struct perf_cpu_map *own_cpus; struct perf_thread_map *threads; + struct perf_mmap *mmap; struct xyarray *fd; struct xyarray *sample_id; u64 *id; diff --git a/tools/lib/perf/include/perf/evsel.h b/tools/lib/perf/include/perf/evsel.h index c82ec39a4ad0..9f5265f2f39f 100644 --- a/tools/lib/perf/include/perf/evsel.h +++ b/tools/lib/perf/include/perf/evsel.h @@ -27,6 +27,8 @@ LIBPERF_API int perf_evsel__open(struct perf_evsel *evsel, struct perf_cpu_map * struct perf_thread_map *threads); LIBPERF_API void perf_evsel__close(struct perf_evsel *evsel); LIBPERF_API void perf_evsel__close_cpu(struct perf_evsel *evsel, int cpu); +LIBPERF_API int perf_evsel__mmap(struct perf_evsel *evsel, int pages); +LIBPERF_API void *perf_evsel__mmap_base(struct perf_evsel *evsel, int cpu, int thread); LIBPERF_API int perf_evsel__read(struct perf_evsel *evsel, int cpu, int thread, struct perf_counts_values *count); LIBPERF_API int perf_evsel__enable(struct perf_evsel *evsel); diff --git a/tools/lib/perf/libperf.map b/tools/lib/perf/libperf.map index 7be1af8a546c..0b993de15830 100644 --- a/tools/lib/perf/libperf.map +++ b/tools/lib/perf/libperf.map @@ -23,6 +23,8 @@ LIBPERF_0.0.1 { perf_evsel__disable; perf_evsel__open; perf_evsel__close; + perf_evsel__mmap; + perf_evsel__mmap_base; perf_evsel__read; perf_evsel__cpus; perf_evsel__threads; -- 2.27.0
