On Sun, Apr 12, 2020 at 5:05 AM Tonghao Zhang <[email protected]>
wrote:

> On Sun, Apr 12, 2020 at 7:57 AM Ravi Kerur <[email protected]> wrote:
> >
> > Hello OvS DPDK team,
> >
> > I am using OvS 2.13.90 and DPDK 19.11 and wanted to use HPET timer
> instead
> > of invariant TSC.
> >
> > Enabled CONFIG_RTE_LIBEAL_USE_HPET=y in DPDK
> >
> > Kernel has
> > CONFIG_HPET_TIMER=y
> > CONFIG_HPET_EMULATE_RTC=y
> > CONFIG_HPET=y
> > CONFIG_HPET_MMAP=y
> > CONFIG_HPET_MMAP_DEFAULT=y
> >
> > cat /sys/devices/system/clocksource/clocksource0/current_clocksource
> > tsc
> > # cat /sys/devices/system/clocksource/clocksource0/available_clocksource
> > tsc hpet acpi_pm
> >
> > OvS crashes at
> >
> > gdb ovsdb-server /core
> > GNU gdb (Ubuntu 8.1-0ubuntu3) 8.1.0.20180409-git
> > Copyright (C) 2018 Free Software Foundation, Inc.
> > License GPLv3+: GNU GPL version 3 or later <
> http://gnu.org/licenses/gpl.html
> > >
> > This is free software: you are free to change and redistribute it.
> > There is NO WARRANTY, to the extent permitted by law.  Type "show
> copying"
> > and "show warranty" for details.
> > This GDB was configured as "x86_64-linux-gnu".
> > Type "show configuration" for configuration details.
> > For bug reporting instructions, please see:
> > <http://www.gnu.org/software/gdb/bugs/>.
> > Find the GDB manual and other documentation resources online at:
> > <http://www.gnu.org/software/gdb/documentation/>.
> > For help, type "help".
> > Type "apropos word" to search for commands related to "word"...
> > Reading symbols from ovsdb-server...done.
> > [New LWP 9729]
> > [Thread debugging using libthread_db enabled]
> > Using host libthread_db library
> "/lib/x86_64-linux-gnu/libthread_db.so.1".
> > Core was generated by `ovsdb-server /usr/local/etc/openvswitch/conf.db
> > -vconsole:emer -vsyslog:err -vf'.
> > Program terminated with signal SIGSEGV, Segmentation fault.
> > #0  0x0000560fc6db8ac1 in rte_get_hpet_cycles ()
> Hi,
> This is a bug on dpdk, NOT ovs.
> I guess that your kernel does't support getentropy which supported in
> 3.17 and your cpu don't support rdseed.
> and that cause a dpdk bug. To workaround, you change: Not tested, hope
> it's useful for you
>
>
You are correct CPU doesn't support RDSEED instruction but RDRAND is
supported.

It's a RT kernel based on 4.19 + RT patches.

Setting CONFIG_RTE_LIBEAL_USE_HPET=n which is the default,'Invariant TSC'
will be used. However, I want to use HPET so should I check with DPDK dev?

Thanks,
Ravi



> diff --git a/lib/librte_eal/linux/eal_timer.c
> b/lib/librte_eal/linux/eal_timer.c
> index a904a8297cd2..4067e46da534 100644
> --- a/lib/librte_eal/linux/eal_timer.c
> +++ b/lib/librte_eal/linux/eal_timer.c
> @@ -26,7 +26,7 @@
>  #include "eal_private.h"
>  #include "eal_internal_cfg.h"
>
> -enum timer_source eal_timer_source = EAL_TIMER_HPET;
> +enum timer_source eal_timer_source = EAL_TIMER_TSC;
>
>  #ifdef RTE_LIBEAL_USE_HPET
>
>
> > (gdb) bt
> > #0  0x0000560fc6db8ac1 in rte_get_hpet_cycles ()
> > #1  0x0000560fc6c482b0 in rte_rand_init ()
> > #2  0x0000560fc6e125bd in __libc_csu_init ()
> > #3  0x00007f5e1f930b28 in __libc_start_main (main=0x560fc6c45940 <main>,
> > argc=14, argv=0x7fff61ae5088, init=0x560fc6e12570 <__libc_csu_init>,
> >     fini=<optimized out>, rtld_fini=<optimized out>,
> > stack_end=0x7fff61ae5078) at ../csu/libc-start.c:266
> > #4  0x0000560fc6c485da in _start ()
> > (gdb) quit
> >
> > RTE_INIT(rte_rand_init)
> > {
> > ...
> > }
> >
> > rte_rand_init is defined as initializer, following diffs won't help,
> >
> > diff --git a/lib/dpdk.c b/lib/dpdk.c
> > index 31450d470..f3d3989c8 100644
> > --- a/lib/dpdk.c
> > +++ b/lib/dpdk.c
> > @@ -405,6 +405,12 @@ dpdk_init__(const struct smap *ovs_other_config)
> >      if (result < 0) {
> >          VLOG_EMER("Unable to initialize DPDK: %s",
> > ovs_strerror(rte_errno));
> >          return false;
> > +    } else {
> > +#ifdef RTE_LIBEAL_USE_HPET
> > +        if (rte_eal_hpet_init(1) < 0) {
> > +            VLOG_ERR("HPET is not enabled, using TSC as default
> timer\n");
> > +        }
> > +#endif
> >      }
> >
> >      if (VLOG_IS_DBG_ENABLED()) {
> >
> > Kindly let me know your inputs on how to overcome this issue.
> >
> > Thanks,
> > Ravi
> > _______________________________________________
> > dev mailing list
> > [email protected]
> > https://mail.openvswitch.org/mailman/listinfo/ovs-dev
>
>
>
> --
> Best regards, Tonghao
>
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