Re: [PATCH tip 0/9] tracing: attach eBPF programs to tracepoints/syscalls/kprobe

2015-01-21 Thread Alexei Starovoitov
On Wed, Jan 21, 2015 at 5:56 PM, Steven Rostedt wrote: > On Wed, 21 Jan 2015 17:49:08 -0800 > Alexei Starovoitov wrote: > > >> > This also makes it keeping events in the soft-disabled state. >> >> I was never able to figure out the use case for soft-disabled state. >> Probably historical before s

Re: [PATCH tip 0/9] tracing: attach eBPF programs to tracepoints/syscalls/kprobe

2015-01-21 Thread Steven Rostedt
On Wed, 21 Jan 2015 17:49:08 -0800 Alexei Starovoitov wrote: > > This also makes it keeping events in the soft-disabled state. > > I was never able to figure out the use case for soft-disabled state. > Probably historical before static_key was done. No, it's not historical at all. The "soft-di

Re: [PATCH tip 0/9] tracing: attach eBPF programs to tracepoints/syscalls/kprobe

2015-01-21 Thread Alexei Starovoitov
On Wed, Jan 21, 2015 at 5:03 PM, Namhyung Kim wrote: > > AFAIK a trigger can be fired before allocating a ring buffer if it > doesn't use the event record (i.e. has filter) or ->post_trigger bit > set (stacktrace). Please see ftrace_trigger_soft_disabled(). yes, but such trigger has no arguments

Re: [PATCH tip 0/9] tracing: attach eBPF programs to tracepoints/syscalls/kprobe

2015-01-21 Thread Namhyung Kim
Hi Alexei, On Fri, Jan 16, 2015 at 10:57:15AM -0800, Alexei Starovoitov wrote: > On Fri, Jan 16, 2015 at 7:02 AM, Steven Rostedt wrote: > > One last thing. If the ebpf is used for anything but filtering, it > > should go into the trigger file. The filtering is only a way to say if > > the event s

Re: Re: Re: [PATCH tip 0/9] tracing: attach eBPF programs to tracepoints/syscalls/kprobe

2015-01-20 Thread Alexei Starovoitov
On Tue, Jan 20, 2015 at 3:57 AM, Masami Hiramatsu wrote: > > Ok, BTW, would you think is it possible to use a reusable small scratchpad > memory for passing arguments? (just a thought) sure. doable, but what's the use case? >> It's not usable for high frequency events which >> need this in-kerne

Re: Re: Re: [PATCH tip 0/9] tracing: attach eBPF programs to tracepoints/syscalls/kprobe

2015-01-20 Thread Masami Hiramatsu
(2015/01/20 12:55), Alexei Starovoitov wrote: > On Mon, Jan 19, 2015 at 6:58 PM, Masami Hiramatsu > wrote: >>> >>> it's done already... one can do the same skb->dev->name logic >>> in kprobe attached program... so from bpf program point of view, >>> tracepoints and kprobes feature-wise are exactly

Re: Re: [PATCH tip 0/9] tracing: attach eBPF programs to tracepoints/syscalls/kprobe

2015-01-19 Thread Alexei Starovoitov
On Mon, Jan 19, 2015 at 6:58 PM, Masami Hiramatsu wrote: >> >> it's done already... one can do the same skb->dev->name logic >> in kprobe attached program... so from bpf program point of view, >> tracepoints and kprobes feature-wise are exactly the same. >> Only input is different. > > No, I meant

Re: Re: [PATCH tip 0/9] tracing: attach eBPF programs to tracepoints/syscalls/kprobe

2015-01-19 Thread Masami Hiramatsu
(2015/01/20 5:48), Alexei Starovoitov wrote: > On Mon, Jan 19, 2015 at 1:52 AM, Masami Hiramatsu > wrote: >> If we can write the script as >> >> int bpf_prog4(s64 write_size) >> { >>... >> } >> >> This will be much easier to play with. > > yes. that's the intent for user space to do. > >>>

Re: [PATCH tip 0/9] tracing: attach eBPF programs to tracepoints/syscalls/kprobe

2015-01-19 Thread Alexei Starovoitov
On Mon, Jan 19, 2015 at 1:52 AM, Masami Hiramatsu wrote: > If we can write the script as > > int bpf_prog4(s64 write_size) > { >... > } > > This will be much easier to play with. yes. that's the intent for user space to do. >> The example of this arbitrary pointer walking is tracex1_kern.c

Re: [PATCH tip 0/9] tracing: attach eBPF programs to tracepoints/syscalls/kprobe

2015-01-19 Thread Masami Hiramatsu
(2015/01/16 13:16), Alexei Starovoitov wrote: > Hi Ingo, Steven, > > This patch set is based on tip/master. > It adds ability to attach eBPF programs to tracepoints, syscalls and kprobes. > > Mechanism of attaching: > - load program via bpf() syscall and receive program_fd > - event_fd = open("/s

Re: [PATCH tip 0/9] tracing: attach eBPF programs to tracepoints/syscalls/kprobe

2015-01-16 Thread Alexei Starovoitov
On Fri, Jan 16, 2015 at 7:02 AM, Steven Rostedt wrote: > On Thu, 15 Jan 2015 20:16:01 -0800 > Alexei Starovoitov wrote: > >> Hi Ingo, Steven, >> >> This patch set is based on tip/master. > > Note, the tracing code isn't maintained in tip/master, but perf code is. I know. I can rebase against lin

Re: [PATCH tip 0/9] tracing: attach eBPF programs to tracepoints/syscalls/kprobe

2015-01-16 Thread Steven Rostedt
On Thu, 15 Jan 2015 20:16:01 -0800 Alexei Starovoitov wrote: > Hi Ingo, Steven, > > This patch set is based on tip/master. Note, the tracing code isn't maintained in tip/master, but perf code is. Using the latest 3.19-rc is probably sufficient for now. Do you have a git repo somewhere that I