From mboxrd@z Thu Jan 1 00:00:00 1970 From: mathieu.desnoyers@efficios.com (Mathieu Desnoyers) Date: Mon, 30 May 2016 13:03:51 +0000 (UTC) Subject: [lttng-dev] scale numbers for LTTNG In-Reply-To: References: <177841807.20574.1464291977964.JavaMail.zimbra@efficios.com> Message-ID: <825187701.22622.1464613431308.JavaMail.zimbra@efficios.com> ----- On May 30, 2016, at 9:16 AM, Vijay Anand wrote: > Hi Mathieu, Jonathan, > I have written python scripts to simulate our requirements. > https://github.com/vjanandr/sampleP/tree/master/lttng > Please refer to the README file for further details about the scripts. > Mathieu, I understand your recommendation to use per UID buffers instead of per > PID buffers. > But I dont seem to understand your suggestion to use filters... > Why ? You can always collect trace data into buffers shared across processes > (per-uid buffers) > and filter after the fact. > <<<<< > Did you mean to say write all traces to a file but filter them while reading > based on maybe process ID ? Yes, this is what I mean, Thanks, Mathieu > Regards, > Vijay > On Fri, May 27, 2016 at 1:16 AM, Mathieu Desnoyers < > mathieu.desnoyers at efficios.com > wrote: >> ----- On May 26, 2016, at 8:23 AM, Vijay Anand < vjanandr85 at gmail.com > wrote: >>> Could anyone please let us know how do we go about this ? >>> Regards, >>> Vijay >>> On Tue, May 24, 2016 at 11:31 AM, Vijay Anand < vjanandr85 at gmail.com > wrote: >>>> Hello Folks, >>>> We have been evaluating LTTNG for use in our production systems for user space >>>> tracing. We have evaluated most of the features supported by LTTNG and very >>>> much see a value add LTTNG brings into our debugging infrastructure. >>>> * Our current requirement is to trace Userspace programs running on linux. >>>> * Each of the linux processes define their own tracepoint providers. >> Sounds like a good design. >>>> * >>>> * We would like to trace event histories of each process independently. >> Why ? You can always collect trace data into buffers shared across processes >> (per-uid buffers) >> and filter after the fact. >>>> * >>>> * We could potentially have 1000s of such processes running simultaneously. >> Especially with that many processes, having per-process buffers will degrade >> your cache >> locality. >>>> * >>>> * We concluded on using a session/channel to trace one tracepoint provider >>>> corresponding to a unique process. >>>> * But I understand we could also create one system wide session and use channels >>>> to trace each of the providers. Either of the approaches seems to work for us. >> Both approach will kill you cache locality with that many process. I don't >> recommend either >> of the two approaches you refer to above. You might want to consider sharing >> your buffers >> across processes. >>>> * But upon evaluating I see that we could create only 25 active process-sessions >>>> and not traces from all the processes are logged. >> We will need much more details on your tracing configuration setup (exact list >> of commands you >> issue to create your tracing sessions). >> Also please detail what you mean by " not traces from all the processes are >> logged". >> What commands do you issue, what is the exact setup, and what is the output >> you observe (exact listing) which leads you to reach this conclusion. >> Thanks, >> Mathieu >>>> * Please note I have tried increasing the buffer size and the number of buffers. >>>> This doesn't help. >>>> * Each of the process trace 52 events at and interval of 1 second each. >>>> * >>>> I have evaluated this with lttng in session,live and snapshot modes and I have >>>> not been getting favourable. >>>> Could you folks share the scale numbers that LTTNG supports, especially when it >>>> comes to tracing user space programs ? >>>> Regards, >>>> Vijay >>>> ​​ >> -- >> Mathieu Desnoyers >> EfficiOS Inc. >> http://www.efficios.com -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com -------------- next part -------------- An HTML attachment was scrubbed... URL: