From: Thomas Monjalon <thomas.monjalon-pdR9zngts4EAvxtiuMwx3w@public.gmane.org>
To: Dmitry Vyal <dmitryvyal-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: "dev-VfR2kkLFssw@public.gmane.org" <dev-VfR2kkLFssw@public.gmane.org>
Subject: Re: Sporadic errors while initializing NICs in example applications, dpdk-1.5.0r1
Date: Fri, 29 Nov 2013 10:20:58 -0800 (PST) [thread overview]
Message-ID: <4967601.BLy1PQ6cQ3@x220> (raw)
In-Reply-To: <3439195.NJQbpGS54N@x220>
Thomas29/11/2013 13:25, Monjalon :
> 29/11/2013 14:53, Dmitry Vyal :
> > On 11/28/2013 03:01 PM, Richardson, Bruce wrote:
> > > [BR] Frequency changes should not affect timers for modern Intel CPUs.
> >
> > The error frequency greatly reduces if I patch
> > loop limit as I described earlier or if I call rte_power_init and
> > rte_power_freq_max as Thomas suggested.
> >
> > But the only way to get rid of them completely is to set performance
> > governor.
>
> Please check that your hardware do not support invariant TSC.
> It would explain why you need to fix frequency.
>
> I attach a simple code to test CPU feature "Invariant TSC".
Note that this feature is called constant_tsc in /proc/cpuinfo:
grep --color -m1 constant_tsc /proc/cpuinfo
It is checked by check_tsc_flags() at DPDK initialization and should print a
warning if missing:
http://dpdk.org/browse/dpdk/commit/?id=e7c8996e13b9abb706ea0de53271346f4f86ca03
--
Thomas
prev parent reply other threads:[~2013-11-29 18:20 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-22 12:29 Sporadic errors while initializing NICs in example applications, dpdk-1.5.0r1 Dmitry Vyal
[not found] ` <528F4E41.2000405-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2013-11-22 12:48 ` Thomas Monjalon
[not found] ` <201311221348.02307.thomas.monjalon-pdR9zngts4EAvxtiuMwx3w@public.gmane.org>
2013-11-27 14:06 ` Dmitry Vyal
[not found] ` <5295FC76.70201-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2013-11-27 14:10 ` jigsaw
2013-11-27 14:42 ` Thomas Monjalon
[not found] ` <201311271542.05288.thomas.monjalon-pdR9zngts4EAvxtiuMwx3w@public.gmane.org>
2013-11-28 11:01 ` Richardson, Bruce
[not found] ` <59AF69C657FD0841A61C55336867B5B01A9781FC-kPTMFJFq+rELt2AQoY/u9bfspsVTdybXVpNB7YpNyf8@public.gmane.org>
2013-11-29 10:53 ` Dmitry Vyal
[not found] ` <52987236.3020707-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2013-11-29 12:25 ` Thomas Monjalon
2013-11-29 12:39 ` Thomas Monjalon
2013-12-06 12:43 ` Dmitry Vyal
2013-11-29 18:20 ` Thomas Monjalon [this message]
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