Re: [Patch net-next v3] tcp: add a tracepoint for tcp retransmission

2017-10-14 Thread David Miller
From: Cong Wang Date: Fri, 13 Oct 2017 13:03:16 -0700 > We need a real-time notification for tcp retransmission > for monitoring. > > Of course we could use ftrace to dynamically instrument this > kernel function too, however we can't retrieve the connection >

Re: [Patch net-next v3] tcp: add a tracepoint for tcp retransmission

2017-10-13 Thread Brendan Gregg
On Fri, Oct 13, 2017 at 3:09 PM, Alexei Starovoitov wrote: > On Fri, Oct 13, 2017 at 01:50:44PM -0700, Brendan Gregg wrote: >> On Fri, Oct 13, 2017 at 1:03 PM, Cong Wang wrote: >> > We need a real-time notification for tcp retransmission >>

Re: [Patch net-next v3] tcp: add a tracepoint for tcp retransmission

2017-10-13 Thread David Ahern
On 10/13/17 2:03 PM, Cong Wang wrote: > diff --git a/include/trace/events/tcp.h b/include/trace/events/tcp.h > new file mode 100644 > index ..3d1cbd072b7e > --- /dev/null > +++ b/include/trace/events/tcp.h > @@ -0,0 +1,68 @@ > +#undef TRACE_SYSTEM > +#define TRACE_SYSTEM tcp > + > +#if

Re: [Patch net-next v3] tcp: add a tracepoint for tcp retransmission

2017-10-13 Thread Alexei Starovoitov
On Fri, Oct 13, 2017 at 01:50:44PM -0700, Brendan Gregg wrote: > On Fri, Oct 13, 2017 at 1:03 PM, Cong Wang wrote: > > We need a real-time notification for tcp retransmission > > for monitoring. > > > > Of course we could use ftrace to dynamically instrument this > >

Re: [Patch net-next v3] tcp: add a tracepoint for tcp retransmission

2017-10-13 Thread Brendan Gregg
On Fri, Oct 13, 2017 at 1:03 PM, Cong Wang wrote: > We need a real-time notification for tcp retransmission > for monitoring. > > Of course we could use ftrace to dynamically instrument this > kernel function too, however we can't retrieve the connection > information at

[Patch net-next v3] tcp: add a tracepoint for tcp retransmission

2017-10-13 Thread Cong Wang
We need a real-time notification for tcp retransmission for monitoring. Of course we could use ftrace to dynamically instrument this kernel function too, however we can't retrieve the connection information at the same time, for example perf-tools [1] reads /proc/net/tcp for socket details, which