From: Thomas Monjalon <thomas.monjalon@6wind.com>
To: Sangjin Han <sangjin@eecs.berkeley.edu>
Cc: dev@dpdk.org
Subject: Re: [dpdk-dev] "No probed ethernet devices" caused by inaccurate msec_delay()
Date: Mon, 27 Jan 2014 10:19:00 +0100 [thread overview]
Message-ID: <201401271019.00293.thomas.monjalon@6wind.com> (raw)
In-Reply-To: <CAPG33HRE3kqHEtn55e_YUoSuwFVTcYz0ZZVjDUXr17TmXqZDQA@mail.gmail.com>
Hello,
27/01/2014 03:56, Sangjin Han:
> Cause: No probed ethernet devices - check that
> CONFIG_RTE_LIBRTE_IGB_PMD=y and that CONFIG_RTE_LIBRTE_EM_PMD=y and
> that CONFIG_RTE_LIBRTE_IXGBE_PMD=y in your configuration file
[...]
> I googled for possible causes and came across a similar case:
> http://openetworking.blogspot.com/2014/01/debugging-no-probed-ethernet-devi
> ces.html
[...]
> msec_delay(4);
[...]
> I think /proc/cpuinfo is not a reliable way to get
> eal_tsc_resolution_hz, since it varies based on the current CPU clock
> frequency. Enforcing applications to run at the max frequency can be
> too restrictive.
Indeed, as described in the quick start page, the highest frequency must be
set: http://dpdk.org/doc/quick-start
> It would be nice if I can bypass set_tsc_freq_from_cpuinfo() in
> set_tsc_freq().
I think it would not solve the problem because your clock is varying and the
TSC calibration must be updated accordingly with different values by core.
Feel free to submit a patch if you find a smart solution.
--
Thomas
next prev parent reply other threads:[~2014-01-27 9:17 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-27 2:56 Sangjin Han
2014-01-27 9:19 ` Thomas Monjalon [this message]
2014-01-28 1:16 ` Sangjin Han
2014-01-28 16:23 ` Thomas Monjalon
2014-01-28 18:13 ` Stephen Hemminger
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