Hi all,
during some tests with dpdk 18.02.2 on RedHat 7 kernel
3.10.0-862.el7.x86_64 using Intel X710 and 2 x Intel(R) Xeon(R) Gold
6130 CPU @ 2.10GHz I found the following.
I put some log in the function set_tsc_freq as you can see below
void
set_tsc_freq(void)
{
uint64_t freq;
freq = get_tsc_freq_arch();
RTE_LOG(WARNING, EAL, "Function get_tsc_freq_arch() returns
%lu\n", freq);
if (!freq)
{
freq = get_tsc_freq();
RTE_LOG(WARNING, EAL, "Function get_tsc_freq() returns
%lu\n", freq);
}
if (!freq)
{
freq = estimate_tsc_freq();
RTE_LOG(WARNING, EAL, "Function estimate_tsc_freq()
returns %lu\n", freq);
}
RTE_LOG(DEBUG, EAL, "TSC frequency is ~%" PRIu64 " KHz\n", freq
/ 1000);
eal_tsc_resolution_hz = freq;
}
the output of this function is:
"EAL: Function get_tsc_freq_arch() returns 2100000000"
but with this value if I use the rte_get_timer_cycles() in my
application and try to convert the return value into seconds I saw that
the more time passes the more date is wrong.
Moreover, if I comment some rows in the set_tsc_freq function this way
void
set_tsc_freq(void)
{
uint64_t freq;
//freq = get_tsc_freq_arch();
//RTE_LOG(WARNING, EAL, "Function get_tsc_freq_arch() returns
%lu\n", freq);
//if (!freq)
//{
freq = get_tsc_freq();
RTE_LOG(WARNING, EAL, "Function get_tsc_freq() returns
%lu\n", freq);
//}
if (!freq)
{
freq = estimate_tsc_freq();
RTE_LOG(WARNING, EAL, "Function estimate_tsc_freq()
returns %lu\n", freq);
}
RTE_LOG(DEBUG, EAL, "TSC frequency is ~%" PRIu64 " KHz\n", freq
/ 1000);
eal_tsc_resolution_hz = freq;
}
the result is
"EAL: Function get_tsc_freq() returns 2094994596"
with this value the conversion into seconds from rte_get_timer_cycles()
is always correct.
Is this a bug? Or am I doing something wrong?
Regards,
Matteo
