* Mathieu Desnoyers ([email protected]) wrote: > * Alexandre Montplaisir ([email protected]) wrote: > > On 13-04-18 02:11 AM, Amit Margalit wrote: > > > Hi, > > > > > > Thank for the quick response. Here is the missing data: > > > > > > UST > > > 2.6.32.12-205 (I had to make a tiny patch to make it compile) > > > MemTotal: 24628852 kB > > > lttng-ust-2.1.2 > > > lttng-tools-2.1.1 > > > lttng-modules-2.1.1 > > > babeltrace-1.1.0 > > > userspace-rcu-0.7.6 > > > > > > Which patch for 4MB? > > > > Hi, > > > > Not sure if it's specifically this one that Matthew was talking about, > > but we have such a patch in the PPA packages. See: > > http://bazaar.launchpad.net/~lttng/lttng-tools/packaging-daily/view/head:/patches/0002-Increase-default-subbuffer-size-to-4MB.patch > > First, it should be noted that lttng enable-channel allow overriding the > subbuffer size. > > It should be noted that lttng-modules 2.2 is going to output even _more_ > events, so I don't think just making the buffers larger by default is > the right approach.
Oh, and I notice that the PPA changes the UST default to 4MB per subbuffer too. That's not going to be pretty for per-pid tracing (which is the default) on a system with 16 CPUs, tracing 100 processes with UST. 4x4MBx16x100 = 25600 MB (25GB) of buffers just for UST. Messing with defaults in packaging seems odd. Mathieu > > I think we need to port the "loglevel" from UST to lttng-modules ASAP, > and assign a "debug" loglevel to events we don't care about by default. > > Thoughts ? > > Thanks, > > Mathieu > > > > > > > > > Thanks, > > > > > > Amit Margalit > > > IBM XIV - Storage Reinvented > > > XIV-NAS Development Team > > > Tel. 03-689-7774 > > > Fax. 03-689-7230 > > > > > > > > > > > > From: Matthew Khouzam <[email protected]> > > > To: <[email protected]> > > > Date: 04/15/2013 05:24 PM > > > Subject: Re: [lttng-dev] Limitations on subbuf_size / num_subbuf? > > > > > > > > > > > > Not at all a n00b question, but could you give some more info? what is > > > your version of LTTng tools, are you using UST or kernel tracing? How > > > much > > > ram is on your system? Kernel version? > > > > > > I actually have the patched lttng that has standard subbuffer sizes of 4 > > > mb, so I have not personnaly seen that problem. But the first thing I > > > would do is upgrade to the latest stable. > > > > > > On 13-04-14 06:49 AM, Amit Margalit wrote: > > > Hello, > > > > > > Sorry for the noob question. I seem to be unable to define the total of > > > subbuf_size * num_subbuf higher than 4MB. I am getting ~30% discarded > > > tracepoint data. > > > > > > Any assistance would be greatly appreciated. > > > > > > Amit Margalit > > > IBM XIV - Storage Reinvented > > > XIV-NAS Development Team > > > Tel. 03-689-7774 > > > Fax. 03-689-7230 > > > > > > _______________________________________________ > > lttng-dev mailing list > > [email protected] > > http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev > > -- > Mathieu Desnoyers > EfficiOS Inc. > http://www.efficios.com > > _______________________________________________ > lttng-dev mailing list > [email protected] > http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com _______________________________________________ lttng-dev mailing list [email protected] http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
