From: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
To: netdev@vger.kernel.org
Cc: "David S. Miller" <davem@davemloft.net>,
Eric Dumazet <eric.dumazet@gmail.com>,
cmetcalf@tilera.com,
Thomas Petazzoni <thomas.petazzoni@free-electrons.com>,
Gregory Clement <gregory.clement@free-electrons.com>,
Simon Guinot <simon.guinot@sequanux.org>,
Willy Tarreau <w@1wt.eu>, Tawfik Bayouk <tawfik@marvell.com>,
Lior Amsalem <alior@marvell.com>,
Simon Guinot <sguinot@lacie.com>
Subject: Re: [PATCH 3/3] net: mvneta: Introduce a software TSO implementation
Date: Mon, 5 May 2014 11:47:02 -0300 [thread overview]
Message-ID: <20140505144702.GB12693@arch.cereza> (raw)
In-Reply-To: <1397170682-19138-4-git-send-email-ezequiel.garcia@free-electrons.com>
Hi all,
On 10 Apr 07:58 PM, Ezequiel Garcia wrote:
[..]
> +
> + /* Calculate expected number of TX descriptors */
> + desc_count = skb_shinfo(skb)->gso_segs * 2 + skb_shinfo(skb)->nr_frags;
> + if ((txq->count + desc_count) >= txq->size)
> + return 0;
> +
Is this calculus correct? Does it give the accurate number of needed
descriptors or is it an approximation?
Tilera's tilegx driver does a much stricter descriptor count (see
tso_count_edescs). This functions loops through the skb_frag_t fragments
as it's done later in the data egress, hence strictly counting the
needed descriptors.
However, as it's a much heavier routine than the one shown above,
I'm wondering if we can get away without it.
Willy, Any ideas here?
--
Ezequiel García, Free Electrons
Embedded Linux, Kernel and Android Engineering
http://free-electrons.com
next prev parent reply other threads:[~2014-05-05 14:47 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-10 22:57 [PATCH 0/3] mvneta: software TSO implementation Ezequiel Garcia
2014-04-10 22:58 ` [PATCH 1/3] net: mvneta: Factorize feature setting Ezequiel Garcia
2014-04-10 22:58 ` [PATCH 2/3] net: mvneta: Clean mvneta_tx() sk_buff handling Ezequiel Garcia
2014-04-10 22:58 ` [PATCH 3/3] net: mvneta: Introduce a software TSO implementation Ezequiel Garcia
2014-04-10 23:16 ` Eric Dumazet
2014-05-05 14:47 ` Ezequiel Garcia [this message]
2014-05-07 6:04 ` Willy Tarreau
2014-05-21 2:11 ` Ben Hutchings
2014-05-22 17:47 ` Ezequiel Garcia
2014-04-11 0:51 ` [PATCH 0/3] mvneta: " David Miller
2014-04-11 1:02 ` Eric Dumazet
2014-04-11 5:48 ` Willy Tarreau
2014-04-11 6:20 ` David Miller
2014-04-11 6:30 ` Willy Tarreau
2014-04-11 16:58 ` David Miller
2014-04-11 19:08 ` Ezequiel Garcia
2014-04-11 19:43 ` Willy Tarreau
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