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From: Richard Schmitt <richard.schmitt@nxp.com>
To: "lttng-dev@lists.lttng.org" <lttng-dev@lists.lttng.org>
Cc: "Nghia (Tommy) Huynh" <nghia.huynh@utexas.edu>
Subject: LTTng user mode performance observation
Date: Wed, 1 Jun 2016 23:29:20 +0000	[thread overview]
Message-ID: <D6EA0E80-F341-43D1-9C4B-780366947A19__46345.0730233037$1464823784$gmane$org@nxp.com> (raw)


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We are trying to use user space LTTng to perform some performance analysis of fast-path layer 3 forwarding.  We have seen that with the tracepoints enabled, we experience about a 30% increase in service time.  This is spread out over two tracepoints so each one is still contributing a good amount.

This fast path is fast, about 300 cycles so we are asking a lot of efficiency of the tracepoint but for comparison, we implemented a simple ring buffer.  When we run with this type of capture, we only experience a 5% increase in service time.

I’m looking for pointers.  We’d rather use LTTng.  Are there ways to tune LTTng ust for ultra high performance requirements.  Perhaps there is  a way we could write directly to ust’s ring buffers, or perhaps preallocate the buffers?

Rich

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             reply	other threads:[~2016-06-01 23:29 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-01 23:29 Richard Schmitt [this message]
     [not found] <D6EA0E80-F341-43D1-9C4B-780366947A19@nxp.com>
2016-06-02 13:10 ` LTTng user mode performance observation Michel Dagenais
2016-06-03  6:23 ` Mathieu Desnoyers

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