On Fri, Aug 9, 2019, at 2:47 PM, Daniel Xu wrote: > It's useful to know [uk]probe's nmissed and nhit stats. For example with > tracing tools, it's important to know when events may have been lost. > debugfs currently exposes a control file to get this information, but > it is not compatible with probes registered with the perf API. > > While bpf programs may be able to manually count nhit, there is no way > to gather nmissed. In other words, it is currently not possible to > retrieve information about FD-based probes. > > This patch adds a new ioctl that lets users query nmissed (as well as > nhit for completeness). We currently only add support for [uk]probes > but leave the possibility open for other probes like tracepoint. > > v1 -> v2: > - More descriptive cover letter > - Make API more generic and support uprobes as well > - Use casters/getters for libbpf instead of single getter > - Fix typos > - Remove size field from ioctl struct > - Split out libbpf.h sync to tools dir to separate commit > > Daniel Xu (4): > tracing/probe: Add PERF_EVENT_IOC_QUERY_PROBE ioctl > libbpf: Add helpers to extract perf fd from bpf_link > tracing/probe: Sync perf_event.h to tools > tracing/probe: Add self test for PERF_EVENT_IOC_QUERY_PROBE > > include/linux/trace_events.h | 12 +++ > include/uapi/linux/perf_event.h | 19 ++++ > kernel/events/core.c | 20 ++++ > kernel/trace/trace_kprobe.c | 23 ++++ > kernel/trace/trace_uprobe.c | 23 ++++ > tools/include/uapi/linux/perf_event.h | 19 ++++ > tools/lib/bpf/libbpf.c | 19 ++++ > tools/lib/bpf/libbpf.h | 8 ++ > tools/lib/bpf/libbpf.map | 6 ++ > .../selftests/bpf/prog_tests/attach_probe.c | 102 ++++++++++++++++++ > 10 files changed, 251 insertions(+) > > -- > 2.20.1 > >
CC PeterZ, whose email I misspelled. Apologies. Daniel
