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From: Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>
To: "Elo, Matias (Nokia - FI/Espoo)" <matias.elo@nokia.com>,
	"dev@dpdk.org" <dev@dpdk.org>
Cc: Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>,
	nd <nd@arm.com>, nd <nd@arm.com>
Subject: Re: [dpdk-dev] eventdev: sw rx adapter enqueue caching
Date: Tue, 7 May 2019 11:12:21 +0000	[thread overview]
Message-ID: <VE1PR08MB514962E65FEE42F3DF2C4A7298310@VE1PR08MB5149.eurprd08.prod.outlook.com> (raw)
Message-ID: <20190507111221.B0d8LBNCOtn1faEeIkWQ5Wo_nDY5_usnuGKb2JNDw74@z> (raw)
In-Reply-To: <53AC5150-DBE2-4E46-9D93-99E01DCEC725@nokia.com>

> 
> Hi,
> 
> The SW eventdev rx adapter has an internal enqueue buffer 'rx_adapter-
> >event_enqueue_buffer', which stores packets received from the NIC until at
> least BATCH_SIZE (=32) packets have been received before enqueueing them
> to eventdev. For example in case of validation testing, where often a small
> number of specific test packets is sent to the NIC, this causes a lot of
> problems. One would always have to transmit at least BATCH_SIZE test
> packets before anything can be received from eventdev. Additionally, if the rx
> packet rate is slow this also adds a considerable amount of additional delay.
> 
> Looking at the rx adapter API and sw implementation code there doesn’t
> seem to be a way to disable this internal caching. In my opinion this
> “functionality" makes testing sw rx adapter so cumbersome that either the
> implementation should be modified to enqueue the cached packets after a
> while (some performance penalty) or there should be some method to
> disable caching. Any opinions how this issue could be fixed?
At the minimum, I would think there should be a compile time option.
From a use case perspective, I think it falls under latency vs throughput considerations. If there is a latency sensitive application, it might not want to wait till 32 packets are received.

> 
> 
> Regards,
> Matias


  parent reply	other threads:[~2019-05-07 11:12 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-07  9:52 Elo, Matias (Nokia - FI/Espoo)
2019-05-07  9:52 ` Elo, Matias (Nokia - FI/Espoo)
2019-05-07 11:12 ` Honnappa Nagarahalli [this message]
2019-05-07 11:12   ` Honnappa Nagarahalli
2019-05-07 12:01   ` Mattias Rönnblom
2019-05-07 12:01     ` Mattias Rönnblom
2019-05-07 12:03     ` Elo, Matias (Nokia - FI/Espoo)
2019-05-07 12:03       ` Elo, Matias (Nokia - FI/Espoo)
2019-05-07 12:13       ` Jerin Jacob Kollanukkaran
2019-05-07 12:13         ` Jerin Jacob Kollanukkaran
2019-05-09 11:24       ` Rao, Nikhil
2019-05-09 11:24         ` Rao, Nikhil
2019-05-09 15:02         ` Elo, Matias (Nokia - FI/Espoo)
2019-05-09 15:02           ` Elo, Matias (Nokia - FI/Espoo)
2019-05-07 11:56 ` Mattias Rönnblom
2019-05-07 11:56   ` Mattias Rönnblom

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