Re: [PATCH v2 bpf-next 1/4] tracing/probe: Add PERF_EVENT_IOC_QUERY_PROBE ioctl

2019-08-13 Thread Daniel Xu
On Tue, Aug 13, 2019, at 2:47 PM, Song Liu wrote: > On Fri, Aug 9, 2019 at 2:48 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

Re: [PATCH v2 bpf-next 1/4] tracing/probe: Add PERF_EVENT_IOC_QUERY_PROBE ioctl

2019-08-13 Thread Song Liu
On Fri, Aug 9, 2019 at 2:48 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

Re: [PATCH v2 bpf-next 1/4] tracing/probe: Add PERF_EVENT_IOC_QUERY_PROBE ioctl

2019-08-13 Thread Andrii Nakryiko
On Mon, Aug 12, 2019 at 5:39 PM Daniel Xu wrote: > > On Mon, Aug 12, 2019, at 8:57 AM, Andrii Nakryiko wrote: > > 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

Re: [PATCH v2 bpf-next 1/4] tracing/probe: Add PERF_EVENT_IOC_QUERY_PROBE ioctl

2019-08-12 Thread Daniel Xu
On Mon, Aug 12, 2019, at 8:57 AM, Andrii Nakryiko wrote: > 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

Re: [PATCH v2 bpf-next 1/4] tracing/probe: Add PERF_EVENT_IOC_QUERY_PROBE ioctl

2019-08-12 Thread Andrii Nakryiko
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

[PATCH v2 bpf-next 1/4] tracing/probe: Add PERF_EVENT_IOC_QUERY_PROBE ioctl

2019-08-09 Thread Daniel Xu
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