[lttng-dev] Limitations on subbuf_size / num_subbuf?

[Alexandre Montplaisir]

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

>
> Thanks,
>
> Amit Margalit
> IBM XIV - Storage Reinvented
> XIV-NAS Development Team
> Tel. 03-689-7774
> Fax. 03-689-7230
>
>
>
> From:   Matthew Khouzam <matthew.khouzam at ericsson.com>
> To:     <lttng-dev at lists.lttng.org>
> 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