Accuracy of rte_get_tsc_hz() compared to linux
Stephen Hemminger
stephen at networkplumber.org
Fri Sep 20 00:02:38 CEST 2024
On Thu, 19 Sep 2024 01:04:40 +0300
Isaac Boukris <iboukris at gmail.com> wrote:
> Hi,
>
> On Intel(R) Xeon(R) Gold 6130 CPU @ 2.10GHz (see lscpu output at the end).
>
> The rte_get_tsc_hz() returns 2100000 KHz but using it causes our
> timestamps to lag behind real time (roughly a sec per 10 min). I
> noticed the kernel uses 2095082 KHz and in fact it gives much better
> results.
>
> dmesg:
> tsc: Detected 2095.082 MHz processor
>
> tsc_freq_khz (custom kmod to exposes kernel's tsc_khz):
> cat /sys/devices/system/cpu/cpu0/tsc_freq_khz
Rather going off into all the weeds of cpuid and whether
the value reported is correct. Perhaps DPDK should just look at the
kernel sysfs files??
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