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From: Gaëtan Rivet <grive@u256.net>
To: Sunil Kumar Kori <skori@marvell.com>
Cc: stephen@networkplumber.org, david.marchand@redhat.com,
	jerinj@marvell.com, dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH v3 1/1] bus/pci: optimise scanning with whitelist/blacklist
Date: Tue, 21 Apr 2020 17:18:17 +0200
Message-ID: <20200421151817.pfcktwfl72mgiuyk@u256.net> (raw)
In-Reply-To: <20200420065554.20138-1-skori@marvell.com>

On 20/04/20 12:25 +0530, Sunil Kumar Kori wrote:
> rte_bus_scan API scans all the available PCI devices irrespective of white
> or black listing parameters then further devices are probed based on white
> or black listing parameters. So unnecessary CPU cycles are wasted during
> rte_pci_scan.
> 
> For Octeontx2 platform with core frequency 2.4 Ghz, rte_bus_scan consumes
> around 26ms to scan around 90 PCI devices but all may not be used by the
> application. So for the application which uses 2 NICs, rte_bus_scan
> consumes few microseconds and rest time is saved with this patch.
> 

Hi Sunil,

The PCI bus was written at first with the understanding that all PCI
devices were scanned and made available on the bus -- the probe will filter
afterward.

Device hotplug and iteration were written with this in mind. Changing
this principle might have unintended consequences in other EAL parts.
I'm not fundamentally against it, but it is not how buses are currently
designed in DPDK.

To me, a one-time 26ms gain is not enough justification to change this
principle. How problematic is this for you? Do you encounter specific
issues due to this delay?

Thanks,
-- 
Gaëtan

  reply	other threads:[~2020-04-21 15:18 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-16  7:55 [dpdk-dev] [PATCH] bus/pci: restricted bus scanning to allowed devices Sunil Kumar Kori
2019-12-16 16:13 ` Stephen Hemminger
2019-12-17 11:00   ` [dpdk-dev] [EXT] " Sunil Kumar Kori
2020-01-21  8:39     ` Sunil Kumar Kori
     [not found]       ` <MN2PR18MB327936807460D9F2AE4894F3B40F0@MN2PR18MB3279.namprd18.prod.outlook.com>
2020-02-27  8:30         ` Sunil Kumar Kori
2020-03-09  6:06           ` Sunil Kumar Kori
2020-04-06  9:32             ` Sunil Kumar Kori
2020-04-06 13:21               ` David Marchand
2020-04-07  9:21                 ` Sunil Kumar Kori
2020-04-07  9:28 ` [dpdk-dev] [PATCH v2 1/1] bus/pci: optimise scanning with whitelist/blacklist Sunil Kumar Kori
2020-04-17  8:30   ` Sunil Kumar Kori
2020-04-17  8:44   ` David Marchand
2020-04-17 11:15     ` [dpdk-dev] [EXT] " Sunil Kumar Kori
2020-04-17 13:25       ` David Marchand
2020-04-17 15:12         ` Sunil Kumar Kori
2020-04-17 15:35           ` David Marchand
2020-04-17 16:00             ` Sunil Kumar Kori
2020-04-20  6:59               ` Sunil Kumar Kori
2020-04-20  6:55   ` [dpdk-dev] [PATCH v3 " Sunil Kumar Kori
2020-04-21 15:18     ` Gaëtan Rivet [this message]
2020-04-22  6:17       ` [dpdk-dev] [EXT] " Sunil Kumar Kori
2020-04-22  9:38         ` Gaëtan Rivet
2020-04-23  7:47           ` Sunil Kumar Kori
2020-04-27 18:43     ` [dpdk-dev] " Gaëtan Rivet
2020-04-28 13:52       ` [dpdk-dev] [EXT] " Sunil Kumar Kori
2020-05-01 11:39     ` [dpdk-dev] [PATCH v4 " Sunil Kumar Kori
2020-05-01 12:40       ` Sunil Kumar Kori
2020-05-01 21:00       ` Gaëtan Rivet
2020-05-02  7:20         ` [dpdk-dev] [EXT] " Sunil Kumar Kori
2020-05-02  7:42       ` [dpdk-dev] [PATCH v5 " Sunil Kumar Kori
2020-05-02 11:27         ` Gaëtan Rivet
2020-05-04 14:17         ` David Marchand
2020-05-05  5:57           ` [dpdk-dev] [EXT] " Sunil Kumar Kori
2020-05-06 12:54           ` [dpdk-dev] " David Marchand
2020-05-11 14:59         ` David Marchand

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