Date: Thu, 22 Aug 2013 10:25:35 -0700 From: hiren panchasara <hiren.panchasara@gmail.com> To: George Neville-Neil <gnn@freebsd.org> Cc: "freebsd-net@freebsd.org" <freebsd-net@freebsd.org>, Mark Johnston <markj@freebsd.org>, freebsd-dtrace@freebsd.org Subject: Re: DTrace network providers Message-ID: <CALCpEUEZYLs0D3ufW4mKRybqgGKcX98%2BVGbnWWRHnRVRo0XDmQ@mail.gmail.com> In-Reply-To: <5CA94104-0489-4DD2-8EC2-D42FF7339E39@freebsd.org> References: <20130821045926.GA17196@raichu> <5CA94104-0489-4DD2-8EC2-D42FF7339E39@freebsd.org>
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On Thu, Aug 22, 2013 at 8:36 AM, George Neville-Neil <gnn@freebsd.org>wrote: > > On Aug 21, 2013, at 1:00 , Mark Johnston <markj@freebsd.org> wrote: > > > Hello! > > > > I've ported the ip, tcp and udp DTrace providers to FreeBSD, following > > the Solaris documentation here: > > > > https://wikis.oracle.com/display/DTrace/ip+Provider > > https://wikis.oracle.com/display/DTrace/tcp+Provider > > https://wikis.oracle.com/display/DTrace/udp+Provider > > > > My implementation of these providers makes use of dynamic translators, > > for which FreeBSD support was added in r254468; this patch won't compile > > with earlier revisions. The use of dynamic translators means that > > existing DTrace scripts which use these providers will just work when run > > on FreeBSD - no modifications needed. In particular, all of the examples > > in the links above will work properly on FreeBSD with my diff. > > > > I've collected a bunch of example scripts for these providers and placed > > them here: > > > > http://people.freebsd.org/~markj/dtrace/network-providers/ > > > > To run one you just need to execute "dtrace -s <script>". > > > > In general these providers make it trivial to monitor or count packets > > and bytes on a per-host/port/protocol/interface basis. One can also do > > neat things like watch TCP connection state transitions in real time > > (tcpstate.d) and measure connection latency. All of the probes > > correspond to logical events in their respective protocol > > implementations; all of the providers have send and receive probes, and > > the tcp provider has a few more. > > > > I didn't have to make any major changes to add support for these > > providers, but I've made a few small tweaks: > > > > 1. Add a little helper function for TCP state changes instead of > > sprinkling a bunch of SDT_PROBE calls throughout the code. > > 2. Set the IPv6 payload size in TCP and UDP before calling ip6_output(). > > This is done for the send probes so that the ipinfo_t argument > > can be used to get the payload size. It's not quite correct since it > > doesn't include the length of IPv6 option headers (they aren't known > > yet), but I think that's ok for the purposes of these providers. > > 3. Set the IPv4 header version in udp_output(). This is already done for > > IPv6. > > > > I'm hoping that none of this (or the rest of the diff) is controversial, > > but I wanted to make sure, so any review would be really appreciated. > > > > The patch is here: > > > > > http://people.freebsd.org/~markj/patches/network-providers/network-providers-1.diff > > > > It depends on r254468. To use it, just recompile the kernel (assuming > > that KDTRACE_HOOKS is enabled) and copy > > $SRC/cddl/lib/libdtrace/{ip,tcp,udp}.d (added by the patch) to > > /usr/lib/dtrace. Then the example scripts I linked above should just > > work. > > > > Excellent work. I'll test these today. > +1. Great work. Updating my laptop right now to test. cheers, Hiren
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