From: Jerin Jacob <jerin.jacob@caviumnetworks.com>
To: Jan Viktorin <viktorin@rehivetech.com>
Cc: Nipun Gupta <nipun.gupta@nxp.com>, "dev@dpdk.org" <dev@dpdk.org>,
"thomas.monjalon@6wind.com" <thomas.monjalon@6wind.com>,
"jianbo.liu@linaro.org" <jianbo.liu@linaro.org>,
Hemant Agrawal <hemant.agrawal@nxp.com>
Subject: Re: [dpdk-dev] [PATCH] eal/armv8: high-resolution cycle counter
Date: Fri, 19 Aug 2016 18:22:18 +0530 [thread overview]
Message-ID: <20160819125217.GA7169@localhost.localdomain> (raw)
In-Reply-To: <20160819142458.42dad72b@pcviktorin.fit.vutbr.cz>
On Fri, Aug 19, 2016 at 02:24:58PM +0200, Jan Viktorin wrote:
> On Fri, 19 Aug 2016 17:16:12 +0530
> Jerin Jacob <jerin.jacob@caviumnetworks.com> wrote:
>
>
> I've got a private kernel driver enabling and disabling (hopefully) properly
> this for ARMv7. If we'd like to merge it, I'd like to have a single module
> or at least single module with 2 implementations...
>
> I can post it if it would be helpful.
I don't think we can use this in production as this may alter PMU state used
by 'perf' etc.I think let it be a debug interface for armv7 and armv8
and disable it by default.
>
> Regards
> Jan
>
> >
> > >
> > > > + *
> > > > + */
> > > > +static inline uint64_t
> > > > +rte_rdtsc(void)
> > > > +{
> > > > + uint64_t tsc;
> > > > +
> > > > + asm volatile("mrs %0, pmccntr_el0" : "=r"(tsc));
> > > > + return tsc;
> > > > +}
> > > > +#endif
> > > >
> > > > static inline uint64_t
> > > > rte_rdtsc_precise(void)
> > > > --
> > > > 2.5.5
> > >
> > > Do you also plan to support performance monitor event counters?
> >
> > No. This patch was inspired by armv7 PMU scheme and its part of DPDK.
> > The sole reason to add this support to catch any performance regression
> > through app/test application.Other than that, I think cntvct_el0 based
> > existing scheme is good enough for all the use cases.
> >
> > >
> > > Regards,
> > > Nipun
> > >
>
>
>
> --
> Jan Viktorin E-mail: Viktorin@RehiveTech.com
> System Architect Web: www.RehiveTech.com
> RehiveTech
> Brno, Czech Republic
next prev parent reply other threads:[~2016-08-19 12:52 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-18 11:51 Jerin Jacob
2016-08-19 9:43 ` Nipun Gupta
2016-08-19 11:46 ` Jerin Jacob
2016-08-19 12:24 ` Jan Viktorin
2016-08-19 12:52 ` Jerin Jacob [this message]
2016-10-04 8:42 ` Thomas Monjalon
2016-08-23 10:01 ` Hemant Agrawal
2016-10-04 8:46 ` Thomas Monjalon
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