Messages in this thread |  | | Date | Wed, 8 Jan 2020 23:08:51 +0100 | From | Jiri Olsa <> | Subject | Re: [PATCH 6/9] perf record: Support synthesizing cgroup events |
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On Tue, Jan 07, 2020 at 10:34:58PM +0900, Namhyung Kim wrote: > Synthesize cgroup events by iterating cgroup filesystem directories. > The cgroup event only saves the portion of cgroup path after the mount > point and the cgroup id (which actually is a file handle). > > Signed-off-by: Namhyung Kim <namhyung@kernel.org> > --- > tools/perf/builtin-record.c | 5 ++ > tools/perf/util/cgroup.c | 3 +- > tools/perf/util/cgroup.h | 1 + > tools/perf/util/event.c | 1 + > tools/perf/util/synthetic-events.c | 119 +++++++++++++++++++++++++++++ > tools/perf/util/synthetic-events.h | 1 + > tools/perf/util/tool.h | 1 + > 7 files changed, 129 insertions(+), 2 deletions(-) > > diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c > index 4c301466101b..2802de9538ff 100644 > --- a/tools/perf/builtin-record.c > +++ b/tools/perf/builtin-record.c > @@ -1397,6 +1397,11 @@ static int record__synthesize(struct record *rec, bool tail) > if (err < 0) > pr_warning("Couldn't synthesize bpf events.\n"); > > + err = perf_event__synthesize_cgroups(tool, process_synthesized_event, > + machine); > + if (err < 0) > + pr_warning("Couldn't synthesize cgroup events.\n"); > + > err = __machine__synthesize_threads(machine, tool, &opts->target, rec->evlist->core.threads, > process_synthesized_event, opts->sample_address, > 1); > diff --git a/tools/perf/util/cgroup.c b/tools/perf/util/cgroup.c > index 4e8ef1db0c94..5147d22b3bda 100644 > --- a/tools/perf/util/cgroup.c > +++ b/tools/perf/util/cgroup.c > @@ -15,8 +15,7 @@ int nr_cgroups; > > static struct rb_root cgroup_tree = RB_ROOT; > > -static int > -cgroupfs_find_mountpoint(char *buf, size_t maxlen) > +int cgroupfs_find_mountpoint(char *buf, size_t maxlen)
out of scope of this change, but could this be added to api/fs/fs.c? it might need more checks then is currently supported, but would be nice to have it under same api as the rest
jirka
> { > FILE *fp; > char mountpoint[PATH_MAX + 1], tokens[PATH_MAX + 1], type[PATH_MAX + 1]; > diff --git a/tools/perf/util/cgroup.h b/tools/perf/util/cgroup.h > index 381583df27c7..9a67060723fa 100644 > --- a/tools/perf/util/cgroup.h > +++ b/tools/perf/util/cgroup.h > @@ -17,6 +17,7 @@ struct cgroup { > > extern int nr_cgroups; /* number of explicit cgroups defined */ > > +int cgroupfs_find_mountpoint(char *buf, size_t maxlen); > struct cgroup *cgroup__get(struct cgroup *cgroup); > void cgroup__put(struct cgroup *cgroup); > > diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c > index 824c038e5c33..28801c867f39 100644 > --- a/tools/perf/util/event.c > +++ b/tools/perf/util/event.c > @@ -33,6 +33,7 @@ > #include "bpf-event.h" > #include "tool.h" > #include "../perf.h" > +#include "cgroup.h" > > static const char *perf_event__names[] = { > [0] = "TOTAL", > diff --git a/tools/perf/util/synthetic-events.c b/tools/perf/util/synthetic-events.c > index cd336eb8886b..36f122cac44f 100644 > --- a/tools/perf/util/synthetic-events.c > +++ b/tools/perf/util/synthetic-events.c > @@ -16,6 +16,7 @@ > #include "util/synthetic-events.h" > #include "util/target.h" > #include "util/time-utils.h" > +#include "util/cgroup.h" > #include <linux/bitops.h> > #include <linux/kernel.h> > #include <linux/string.h> > @@ -413,6 +414,124 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool, > return rc; > } > > +static int perf_event__synthesize_cgroup(struct perf_tool *tool, > + union perf_event *event, > + char *path, size_t mount_len, > + perf_event__handler_t process, > + struct machine *machine) > +{ > + size_t event_size = sizeof(event->cgroup) - sizeof(event->cgroup.path); > + size_t path_len = strlen(path) - mount_len + 1; > + struct { > + struct file_handle fh; > + uint64_t cgroup_id; > + } handle; > + int mount_id; > + > + while (path_len % sizeof(u64)) > + path[mount_len + path_len++] = '\0'; > + > + memset(&event->cgroup, 0, event_size); > + > + event->cgroup.header.type = PERF_RECORD_CGROUP; > + event->cgroup.header.size = event_size + path_len + machine->id_hdr_size; > + > + handle.fh.handle_bytes = sizeof(handle.cgroup_id); > + if (name_to_handle_at(AT_FDCWD, path, &handle.fh, &mount_id, 0) < 0) { > + pr_debug("stat failed: %s\n", path); > + return -1; > + } > + > + event->cgroup.id = handle.cgroup_id; > + strncpy(event->cgroup.path, path + mount_len, path_len); > + memset(event->cgroup.path + path_len, 0, machine->id_hdr_size); > + > + if (perf_tool__process_synth_event(tool, event, machine, process) < 0) { > + pr_debug("process synth event failed\n"); > + return -1; > + } > + > + return 0; > +} > + > +static int perf_event__walk_cgroup_tree(struct perf_tool *tool, > + union perf_event *event, > + char *path, size_t mount_len, > + perf_event__handler_t process, > + struct machine *machine) > +{ > + size_t pos = strlen(path); > + DIR *d; > + struct dirent *dent; > + int ret = 0; > + > + if (perf_event__synthesize_cgroup(tool, event, path, mount_len, > + process, machine) < 0) > + return -1; > + > + d = opendir(path); > + if (d == NULL) { > + pr_debug("failed to open directory: %s\n", path); > + return -1; > + } > + > + while ((dent = readdir(d)) != NULL) { > + if (dent->d_type != DT_DIR) > + continue; > + if (!strcmp(dent->d_name, ".") || > + !strcmp(dent->d_name, "..")) > + continue; > + > + if (path[pos - 1] != '/') > + strcat(path, "/"); > + strcat(path, dent->d_name); > + > + ret = perf_event__walk_cgroup_tree(tool, event, path, > + mount_len, process, machine); > + if (ret < 0) > + break; > + > + path[pos] = '\0'; > + } > + > + closedir(d); > + return ret; > +} > + > +int perf_event__synthesize_cgroups(struct perf_tool *tool, > + perf_event__handler_t process, > + struct machine *machine) > +{ > + union perf_event event; > + char *cgrp_root; > + size_t mount_len; /* length of mount point in the path */ > + int ret = -1; > + > + cgrp_root = malloc(PATH_MAX); > + if (cgrp_root == NULL) > + return -1; > + > + if (cgroupfs_find_mountpoint(cgrp_root, PATH_MAX) < 0) { > + pr_debug("cannot find cgroup mount point\n"); > + goto out; > + } > + > + mount_len = strlen(cgrp_root); > + /* make sure the path starts with a slash (after mount point) */ > + strcat(cgrp_root, "/"); > + > + if (perf_event__walk_cgroup_tree(tool, &event, cgrp_root, mount_len, > + process, machine) < 0) > + goto out; > + > + ret = 0; > + > +out: > + free(cgrp_root); > + > + return ret; > +} > + > int perf_event__synthesize_modules(struct perf_tool *tool, perf_event__handler_t process, > struct machine *machine) > { > diff --git a/tools/perf/util/synthetic-events.h b/tools/perf/util/synthetic-events.h > index baead0cdc381..e7a3e9589738 100644 > --- a/tools/perf/util/synthetic-events.h > +++ b/tools/perf/util/synthetic-events.h > @@ -45,6 +45,7 @@ int perf_event__synthesize_kernel_mmap(struct perf_tool *tool, perf_event__handl > int perf_event__synthesize_mmap_events(struct perf_tool *tool, union perf_event *event, pid_t pid, pid_t tgid, perf_event__handler_t process, struct machine *machine, bool mmap_data); > int perf_event__synthesize_modules(struct perf_tool *tool, perf_event__handler_t process, struct machine *machine); > int perf_event__synthesize_namespaces(struct perf_tool *tool, union perf_event *event, pid_t pid, pid_t tgid, perf_event__handler_t process, struct machine *machine); > +int perf_event__synthesize_cgroups(struct perf_tool *tool, perf_event__handler_t process, struct machine *machine); > int perf_event__synthesize_sample(union perf_event *event, u64 type, u64 read_format, const struct perf_sample *sample); > int perf_event__synthesize_stat_config(struct perf_tool *tool, struct perf_stat_config *config, perf_event__handler_t process, struct machine *machine); > int perf_event__synthesize_stat_events(struct perf_stat_config *config, struct perf_tool *tool, struct evlist *evlist, perf_event__handler_t process, bool attrs); > diff --git a/tools/perf/util/tool.h b/tools/perf/util/tool.h > index 472ef5eb4068..3fb67bd31e4a 100644 > --- a/tools/perf/util/tool.h > +++ b/tools/perf/util/tool.h > @@ -79,6 +79,7 @@ struct perf_tool { > bool ordered_events; > bool ordering_requires_timestamps; > bool namespace_events; > + bool cgroup_events; > bool no_warn; > enum show_feature_header show_feat_hdr; > }; > -- > 2.24.1.735.g03f4e72817-goog >
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