lkml.org 
[lkml]   [2010]   [Feb]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH 05/11] perf: New PERF_EVENT_IOC_INJECT ioctl
    On Wed, Feb 03, 2010 at 10:14:29AM +0100, Frederic Weisbecker wrote:
    > The PERF_EVENT_IOC_INJECT perf event ioctl can be used to inject
    > events, if the corresponding pmu and event supports it.
    >
    > On trace events, it will call the inject callback, usually reserved
    > for events that need to catch up with the user.
    >
    > Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
    > Cc: Peter Zijlstra <peterz@infradead.org>
    > Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
    > Cc: Steven Rostedt <rostedt@goodmis.org>
    > Cc: Paul Mackerras <paulus@samba.org>
    > Cc: Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
    > Cc: Li Zefan <lizf@cn.fujitsu.com>
    > Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
    > Cc: Masami Hiramatsu <mhiramat@redhat.com>
    > Cc: Jens Axboe <jens.axboe@oracle.com>
    > ---
    > include/linux/perf_event.h | 2 ++
    > kernel/perf_event.c | 23 +++++++++++++++++++++++
    > 2 files changed, 25 insertions(+), 0 deletions(-)
    >
    > diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
    > index 556b0f4..d2e83f0 100644
    > --- a/include/linux/perf_event.h
    > +++ b/include/linux/perf_event.h
    > @@ -228,6 +228,7 @@ struct perf_event_attr {
    > #define PERF_EVENT_IOC_PERIOD _IOW('$', 4, __u64)
    > #define PERF_EVENT_IOC_SET_OUTPUT _IO ('$', 5)
    > #define PERF_EVENT_IOC_SET_FILTER _IOW('$', 6, char *)
    > +#define PERF_EVENT_IOC_INJECT _IO ('$', 7)
    >
    > enum perf_event_ioc_flags {
    > PERF_IOC_FLAG_GROUP = 1U << 0,
    > @@ -513,6 +514,7 @@ struct pmu {
    > void (*disable) (struct perf_event *event);
    > void (*read) (struct perf_event *event);
    > void (*unthrottle) (struct perf_event *event);
    > + void (*inject) (struct perf_event *event);
    > };
    >
    > /**
    > diff --git a/kernel/perf_event.c b/kernel/perf_event.c
    > index 40f8b07..e4dfd12 100644
    > --- a/kernel/perf_event.c
    > +++ b/kernel/perf_event.c
    > @@ -2151,6 +2151,26 @@ unlock:
    > return ret;
    > }
    >
    > +static void __perf_event_inject(void *info)
    > +{
    > + struct perf_event *event = info;
    > +
    > + event->pmu->inject(event);
    > +}
    > +
    > +static int perf_event_inject(struct perf_event *event)
    > +{
    > + struct perf_event_context *ctx = event->ctx;
    > + struct task_struct *task = ctx->task;
    > +
    > + if (!event->pmu->inject || task)
    > + return -EINVAL;
    > +
    > + smp_call_function_single(event->cpu, __perf_event_inject, event, 1);
    > +



    Ah, I forgot to say. Injection is only supported on cpu
    bound events (non-task bound). Because if it is task-bound,
    we can't ensure we can inject while the event is scheduled,
    not sure how to fix this.



    \
     
     \ /
      Last update: 2010-02-03 10:23    [W:0.025 / U:29.276 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site