Messages in this thread Patch in this message | | | Date | Tue, 23 May 2017 18:31:34 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH net-next 1/2] perf, bpf: add support for HW_CACHE and RAW events |
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On Tue, May 23, 2017 at 07:38:08AM -0700, Alexei Starovoitov wrote: > On 5/23/17 12:42 AM, Peter Zijlstra wrote: > > On Mon, May 22, 2017 at 03:48:39PM -0700, Alexei Starovoitov wrote: > > > From: Teng Qin <qinteng@fb.com> > > > > > > This commit adds support for attach BPF program to RAW and HW_CACHE type > > > events, and support for read HW_CACHE type event counters in BPF > > > program. Existing code logic already supports them, so this commit is > > > just update Enum value checks. > > > > So what I'm missing is why they were not supported previously, and what > > changed to allow it now. > > that code path simply wasn't tested previously. Nothing changed on > bpf side and on perf side. > Why it wasn't added on day one? There was no demand. Now people > use bpf more and more and few folks got confused that these types > of perf events were not supported, hence we're adding it.
OK. Is there anything stopping people from wanting to use the dynamic types, as found in:
/sys/bus/event_source/devices/*/type
?
In which case, do we want something like this instead?
diff --git a/kernel/events/core.c b/kernel/events/core.c index 971f7259108f..4aa5f3011cf8 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -8063,12 +8063,8 @@ static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd) bool is_kprobe, is_tracepoint; struct bpf_prog *prog; - if (event->attr.type == PERF_TYPE_HARDWARE || - event->attr.type == PERF_TYPE_SOFTWARE) - return perf_event_set_bpf_handler(event, prog_fd); - if (event->attr.type != PERF_TYPE_TRACEPOINT) - return -EINVAL; + return perf_event_set_bpf_handler(event, prog_fd); if (event->tp_event->prog) return -EEXIST;
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