On Tue, Apr 14, 2020 at 12:07 PM Stephen Hemminger
<step...@networkplumber.org> wrote:
>
> On Sun, 12 Apr 2020 16:27:53 +0800
> xiangxia.m....@gmail.com wrote:
>
> > From: Tonghao Zhang <xiangxia.m....@gmail.com>
> >
> > When rte_rand_init is invoked, and the kernel
> > (kernel version < 3.17) running dpdk does't support
> > *getentropy, at the same time, the cpu does't support
> > rdseed, the rte_rand_init will invoke rte_get_timer_cycles
> > which function will invoke rte_get_hpet_cycles
> > (RTE_LIBEAL_USE_HPET was enabled) while *eal_hpet is not
> > allocated.
> >
> > Fixes: faf8fd252785 ("eal: improve entropy for initial PRNG seed")
> > Fixes: 3f002f069612 ("eal: replace libc-based random generation with LFSR")
> >
> > Cc: sta...@dpdk.org
> >
> > Signed-off-by: Tonghao Zhang <xiangxia.m....@gmail.com>
>
> Are you sure this patch won't change current default to use HPET (which is
> slower)?
In rte_eal_timer_init (linux/eal_timer.c)， it will set
eal_timer_source = EAL_TIMER_TSC too.
So after rte_eal_init, eal_timer_source == EAL_TIMER_TSC which is the
default timer source actually.
Then this patch will affect RTE_INIT function which invoke
rte_get_timer_cycles. but hpet is not available yet.
> Before this patch users would get TSC as default.
--
Best regards, Tonghao
