Re: Sporadic errors while initializing NICs in example applications, dpdk-1.5.0r1

[Dmitry Vyal <dmitryvyal-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

Hmm, that's strange. I don't know how to interpret my observations then. 
I have access to two platforms, one is based on Intel(R) Xeon(R) CPU 
E3-1230 V2 @ 3.30GHz and another on Intel(R) Xeon(R) CPU E3-1270 v3 @ 
3.50GHz. Both running ubuntu-12.04 server. I see repeating errors on NIC 
initialisation phase. 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.

On 11/28/2013 03:01 PM, Richardson, Bruce wrote:
>> It's probably due to a frequency scaling.
>> The timer based is initialized when DPDK initialize and the CPU can change
>> its frequency, breaking next timers.
>>
>> The fix is to control the CPU frequency.
>> Please try this, without your patch:
>> 	for g in /sys/devices/system/cpu/*/cpufreq/scaling_governor; do
>> echo performance >$g; done The right fix for applications (examples and
>> testpmd included) could be to call rte_power_init(). Patches are welcomed.
>>
> [BR] Frequency changes should not affect timers for modern Intel CPUs. Please see the " Intel(r) 64 and IA-32 Architectures Software Developer's Manual" Volume 3 (http://www.intel.com/content/dam/www/public/us/en/documents/manuals/64-ia-32-architectures-software-developer-system-programming-manual-325384.pdf) , Section 17.13 for more details on this.
>