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From: Harman Kalra <hkalra@marvell.com>
To: "Burakov, Anatoly" <anatoly.burakov@intel.com>
Cc: <dev@dpdk.org>, David Hunt <david.hunt@intel.com>,
	<liang.j.ma@intel.com>,  <reshma.pattan@intel.com>
Subject: Re: [dpdk-dev] [EXT] Re: [PATCH 3/3] l3fwd-power: add interrupt-only mode
Date: Tue, 2 Jun 2020 17:46:55 +0530
Message-ID: <20200602121654.GA106816@outlook.office365.com> (raw)
In-Reply-To: <20200602102259.GA54715@outlook.office365.com>

On Tue, Jun 02, 2020 at 03:53:07PM +0530, Harman Kalra wrote:
> On Mon, Jun 01, 2020 at 01:50:26PM +0100, Burakov, Anatoly wrote:
> > On 30-May-20 11:02 AM, Harman Kalra wrote:
> > > On Fri, May 29, 2020 at 03:19:45PM +0100, Burakov, Anatoly wrote:
> > > > External Email
> > > > 
> > > > ----------------------------------------------------------------------
> > > > On 29-May-20 2:19 PM, Harman Kalra wrote:
> > > > 
> > > > > >    	if (ret < 0)
> > > > > >    		rte_exit(EXIT_FAILURE, "Invalid L3FWD parameters\n");
> > > > > > -	if (app_mode != APP_MODE_TELEMETRY && init_power_library())
> > > > > > +	if (app_mode == APP_MODE_DEFAULT)
> > > > > > +		app_mode = APP_MODE_LEGACY;
> > > > > > +
> > > > > > +	/* only legacy and empty poll mode rely on power library */
> > > > > > +	if ((app_mode == APP_MODE_LEGACY || app_mode == APP_MODE_EMPTY_POLL) &&
> > > > > > +			init_power_library())
> > > > > >    		rte_exit(EXIT_FAILURE, "init_power_library failed\n");
> > > > > Hi,
> > > > > 
> > > > > Rather than just exiting from here can we have a else condition to
> > > > > automatically enter into the "interrupt only" mode.
> > > > > Please correct me if I am missing something.
> > > > 
> > > > Hi,
> > > > 
> > > > Thanks for your review. I don't think silently proceeding is a good idea. If
> > > > the user wants interrupt-only mode, they should request it. Silently falling
> > > > back to interrupt-only mode will create an illusion of successful
> > > > initialization and set the wrong expectation for how the application will
> > > > behave.
> > > > 
> > > 
> > > Hi,
> > > 
> > > Thanks for the explanation which even I also believe is logically perfect.
> > > 
> > > But since l3fwd-power is an old application and has many users around
> > > which are currently using this app in interrupt only mode without giving
> > > an extra argument. But suddenly they will start getting failure messages with
> > > the new patchset.
> > > 
> > > My only intent with else condition was backward compatibility.
> > > Or may be we can have more descriptive failure message, something like
> > > "init_power_library failed, check manual for other modes".
> > > 
> > > Thanks
> > > Harman
> > > 
> > > 
> > 
> > I think we can compormise on an informative log message suggesting to use
> > interrupt mode. I'm not keen on reverting to previous buggy behavior :)
> > 
> Hi
> 
> I am not insisting to revert to previous behavior, I am just trying to
> highlight some probable issues that many users might face as its an old
> application.
> Since many arm based soc might not be supporting frequency scaling, can
> we add the following check as soon as the application starts, probe the
> platform if it supports frequency scaling, if not automatically set the
> mode to interrupt mode, something like:
> if (access("/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor",
> 			F_OK))
> 	app_mode = APP_MODE_INTERRUPT;

Sorry, no direct check in application but we can introduce a new API in
power library:
   bool rte_is_freq_scaling() {
	   return  access("/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor",
			   F_OK);
   }

and in the application we can use "rte_is_freq_scaling()" at the start.

> 
> 
> Thanks
> Harman
> 
> > > > -- 
> > > > Thanks,
> > > > Anatoly
> > 
> > 
> > -- 
> > Thanks,
> > Anatoly

  reply	other threads:[~2020-06-02 12:17 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-28  9:13 [dpdk-dev] [PATCH 0/3] Add interrupt-only mode to l3fwd-power Anatoly Burakov
2020-05-28  9:13 ` [dpdk-dev] [PATCH 1/3] l3fwd-power: disable interrupts by default Anatoly Burakov
2020-05-28  9:13 ` [dpdk-dev] [PATCH 2/3] l3fwd-power: only allow supported power library envs Anatoly Burakov
2020-05-28  9:13 ` [dpdk-dev] [PATCH 3/3] l3fwd-power: add interrupt-only mode Anatoly Burakov
2020-05-29 13:19   ` Harman Kalra
2020-05-29 14:19     ` Burakov, Anatoly
2020-05-30 10:02       ` [dpdk-dev] [EXT] " Harman Kalra
2020-06-01 12:50         ` Burakov, Anatoly
2020-06-02 10:23           ` Harman Kalra
2020-06-02 12:16             ` Harman Kalra [this message]
2020-06-15 11:31               ` Burakov, Anatoly
2020-06-15 11:43                 ` Jerin Jacob
2020-06-15 15:05                   ` Burakov, Anatoly
2020-06-15 15:21                     ` Jerin Jacob
2020-06-15 15:45                       ` Burakov, Anatoly
2020-06-15 16:29                         ` Jerin Jacob
2020-06-16  9:31                           ` Burakov, Anatoly
2020-06-16 17:09                             ` Jerin Jacob
2020-06-08  1:24 ` [dpdk-dev] [PATCH 0/3] Add interrupt-only mode to l3fwd-power Wang, Yinan
2020-06-18 17:18 ` [dpdk-dev] [PATCH v2 0/7] " Anatoly Burakov
2020-06-19 10:53   ` [dpdk-dev] [PATCH v3 " Anatoly Burakov
2020-07-11 11:35     ` Thomas Monjalon
2020-06-19 10:53   ` [dpdk-dev] [PATCH v3 1/7] l3fwd-power: disable interrupts by default Anatoly Burakov
2020-06-19 10:53   ` [dpdk-dev] [PATCH v3 2/7] l3fwd-power: only allow supported power library envs Anatoly Burakov
2020-06-19 10:53   ` [dpdk-dev] [PATCH v3 3/7] l3fwd-power: code style and flow fixes Anatoly Burakov
2020-06-19 10:53   ` [dpdk-dev] [PATCH v3 4/7] l3fwd-power: add support for requesting legacy mode Anatoly Burakov
2020-06-19 10:53   ` [dpdk-dev] [PATCH v3 5/7] l3fwd-power: add interrupt-only mode Anatoly Burakov
2020-06-19 10:53   ` [dpdk-dev] [PATCH v3 6/7] power: add API to probe support for a specific env Anatoly Burakov
2020-06-19 10:53   ` [dpdk-dev] [PATCH v3 7/7] l3fwd-power: add auto-selection of default mode Anatoly Burakov
2020-07-11 10:07     ` Thomas Monjalon
2020-06-18 17:18 ` [dpdk-dev] [PATCH v2 1/7] l3fwd-power: disable interrupts by default Anatoly Burakov
2020-06-18 17:18 ` [dpdk-dev] [PATCH v2 2/7] l3fwd-power: only allow supported power library envs Anatoly Burakov
2020-06-18 17:18 ` [dpdk-dev] [PATCH v2 3/7] l3fwd-power: code style and flow fixes Anatoly Burakov
2020-06-18 17:18 ` [dpdk-dev] [PATCH v2 4/7] l3fwd-power: add support for requesting legacy mode Anatoly Burakov
2020-06-18 17:18 ` [dpdk-dev] [PATCH v2 5/7] l3fwd-power: add interrupt-only mode Anatoly Burakov
2020-06-18 17:18 ` [dpdk-dev] [PATCH v2 6/7] power: add API to probe support for a specific env Anatoly Burakov
2020-06-18 17:18 ` [dpdk-dev] [PATCH v2 7/7] l3fwd-power: add auto-selection of default mode Anatoly Burakov
2020-06-19  7:37   ` [dpdk-dev] [EXT] " Harman Kalra
2020-06-19  9:56     ` Burakov, Anatoly

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