<div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Sep 19, 2017 at 10:57 PM, Jonathan Rajotte-Julien <span dir="ltr"><<a href="mailto:jonathan.rajotte-julien@efficios.com" target="_blank">jonathan.rajotte-julien@efficios.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class="">On Tue, Sep 19, 2017 at 03:53:27PM +0800, liguang li wrote:<br>
> Hi,<br>
</span><span class="">> On Mon, Sep 18, 2017 at 11:18 PM, Jonathan Rajotte-Julien<br>
</span><span class="">> <[1]<a href="mailto:jonathan.rajotte-julien@efficios.com">jonathan.rajotte-julien@<wbr>efficios.com</a>> wrote:<br>
><br>
> Hi,<br>
> On Mon, Sep 18, 2017 at 11:32:07AM +0800, liguang li wrote:<br>
> > Hi,<br>
> ><br>
> > Create a session in live-reading mode, run a application which<br>
> having very<br>
> > high event throughput, then prints<br>
> > the events with babeltrace. We found the live trace viewer are<br>
> viewing<br>
> > events a few seconds ago, and as time<br>
><br>
> Could you provide us the version used for babeltrace, lttng-tools and<br>
> lttng-ust?<br>
><br>
> Babeltrace: 1.5.1<br>
<br>
</span>Update to babeltrace 1.5.3.<br>
<br>
> Lttng-tools: 2.8.6<br>
<br>
Update to lttng-tools 2.8.8<br>
<span class=""><br>
> Lttng-ust: 2.8.2<br>
><br>
> > goes on, the delay will be bigger and bigger.<br>
><br>
> A similar issues was observed a couple months ago, which implicated<br>
> multiple delayed ack<br>
> problems during communication between lttng-relayd and babeltrace.<br>
><br>
> The following fixes were merged:<br>
><br>
> [1]<br>
</span>> [2]<a href="https://github.com/lttng/lttng-tools/commit/b6025e9476332b75eb8184345c3eb3e924780088" rel="noreferrer" target="_blank">https://github.com/lttng/<wbr>lttng-tools/commit/<wbr>b6025e9476332b75eb8184345c3eb3<wbr>e924780088</a><br>
> [2]<br>
> [3]<a href="https://github.com/efficios/babeltrace/commit/de417d04317ca3bc30f59685a9d19de670e4b11d" rel="noreferrer" target="_blank">https://github.com/<wbr>efficios/babeltrace/commit/<wbr>de417d04317ca3bc30f59685a9d19d<wbr>e670e4b11d</a><br>
> [3]<br>
> [4]<a href="https://github.com/efficios/babeltrace/commit/4594dbd8f7c2af2446a3e310bee74ba4a2e9d648" rel="noreferrer" target="_blank">https://github.com/<wbr>efficios/babeltrace/commit/<wbr>4594dbd8f7c2af2446a3e310bee74b<wbr>a4a2e9d648</a><br>
<span class="">><br>
> In the event that you are already using an updated version of babeltrace<br>
> and<br>
> lttng-tools, it would be pertinent to provide us with a simple<br>
> reproducer so we<br>
> can assess the issue.<br>
<br>
</span>The version you are using does not include the mentioned fixes. Please update<br>
and redo your experiment.<br>
<br></blockquote><div><br></div><div>Test this issue in the version you have listed, the issue still exists.<br></div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Cheers<br>
<span class=""><br>
><br>
> <br>
> Steps:<br>
> lttng create session --live -U net://*<br>
> lttng enable-channel -s session -u ch1<br>
> lttng enable-event -s session -c ch1 -u -a<br>
> lttng start<br>
> <br>
> Run a high event throughput application, which is multithreaded<br>
> application.<br></span></blockquote><div><br></div><div>In the multithreaded application, each tracepoint will have the wall <br></div><div>time of the system,then we can easily reproduce this issue through</div><div> comparing the time of recorded event and the system wall time.<br></div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class="">
> babeltrace -i lttng-live net://*<br>
> <br>
> After a while, we found the timestamp of the event in the babeltrace is<br>
> different with the time in host<br>
> which run the application. And the delay will be bigger and bigger with<br>
> time goes.<br>
> <br>
><br>
> Cheers<br>
> > I checked the source code, found Babeltrace in live-reading mode<br>
> will read<br>
> > the recorded events in the CTF<br>
> > files, and then parse and print it in a single thread. The process<br>
> is a<br>
> > little slow, do you have any ideas to<br>
> > improve the process.<br></span></blockquote><div><br></div><div>From my understanding of the source code, the process of parse and <br></div><div>print event will consume a lot of time. For example, the multithreaded</div><div> application will consume 3 CPUs, in a specified time,3 subbuffers will</div><div> be filled and sent to lttng-relayd daemon, recorded into the CTF files. <br></div><div>If in the specified time, babeltrace only handled 2 subbuffers' event,</div><div> thenthe issue will happens.<br></div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class="">
> > Thanks,<br>
> > Liguang<br>
><br>
> > ______________________________<wbr>_________________<br>
> > lttng-dev mailing list<br>
</span>> > [5]<a href="mailto:lttng-dev@lists.lttng.org">lttng-dev@lists.lttng.org</a><br>
> > [6]<a href="https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev" rel="noreferrer" target="_blank">https://lists.lttng.org/<wbr>cgi-bin/mailman/listinfo/<wbr>lttng-dev</a><br>
><br>
> --<br>
> Jonathan Rajotte-Julien<br>
> EfficiOS<br>
><br>
> References<br>
><br>
> Visible links<br>
> 1. mailto:<a href="mailto:jonathan.rajotte-julien@efficios.com">jonathan.rajotte-<wbr>julien@efficios.com</a><br>
> 2. <a href="https://github.com/lttng/lttng-tools/commit/b6025e9476332b75eb8184345c3eb3e924780088" rel="noreferrer" target="_blank">https://github.com/lttng/<wbr>lttng-tools/commit/<wbr>b6025e9476332b75eb8184345c3eb3<wbr>e924780088</a><br>
> 3. <a href="https://github.com/efficios/babeltrace/commit/de417d04317ca3bc30f59685a9d19de670e4b11d" rel="noreferrer" target="_blank">https://github.com/efficios/<wbr>babeltrace/commit/<wbr>de417d04317ca3bc30f59685a9d19d<wbr>e670e4b11d</a><br>
> 4. <a href="https://github.com/efficios/babeltrace/commit/4594dbd8f7c2af2446a3e310bee74ba4a2e9d648" rel="noreferrer" target="_blank">https://github.com/efficios/<wbr>babeltrace/commit/<wbr>4594dbd8f7c2af2446a3e310bee74b<wbr>a4a2e9d648</a><br>
> 5. mailto:<a href="mailto:lttng-dev@lists.lttng.org">lttng-dev@lists.lttng.<wbr>org</a><br>
> 6. <a href="https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev" rel="noreferrer" target="_blank">https://lists.lttng.org/cgi-<wbr>bin/mailman/listinfo/lttng-dev</a><br>
<span class="HOEnZb"><font color="#888888"><br>
--<br>
Jonathan Rajotte-Julien<br>
EfficiOS<br>
</font></span></blockquote></div><br></div></div>