From: David Decotigny <david.decotigny@google.com>
To: Stephen Hemminger <shemminger@vyatta.com>,
Ben Hutchings <bhutchings@solarflare.com>
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
"David S. Miller" <davem@davemloft.net>,
Ian Campbell <ian.campbell@citrix.com>,
Eric Dumazet <eric.dumazet@gmail.com>,
Jeff Kirsher <jeffrey.t.kirsher@intel.com>,
Jiri Pirko <jpirko@redhat.com>, Joe Perches <joe@perches.com>,
Szymon Janc <szymon@janc.net.pl>,
Richard Jones <rick.jones2@hp.com>,
Ayaz Abdulla <AAbdulla@nvidia.com>
Subject: Re: [PATCH net-next v5 07/10] forcedeth: implement ndo_get_stats64() API
Date: Wed, 16 Nov 2011 11:25:23 -0800 [thread overview]
Message-ID: <CAG88wWa7UsPSfX_NdNDkQeuWN0LYYDVckShgDj9GvMq2mtrpbQ@mail.gmail.com> (raw)
In-Reply-To: <1321463694.2709.1.camel@bwh-desktop>
Thanks for your feedback on these concerns.
On Wed, Nov 16, 2011 at 9:14 AM, Ben Hutchings
<bhutchings@solarflare.com> wrote:
> On Wed, 2011-11-16 at 08:55 -0800, Stephen Hemminger wrote:
>> Or realize that the Tx side is single threaded by dev->xmit_lock already
>> and the Rx side is single threaded by NAPI.
>
> Right.
Yes, that's what I meant by "Each software stat field is updated by
one single writer." in a previous email. However, I think that TX and
RX paths are not always synchronized. So I'm afraid that if I'm using
a single seqcount, I might run into trouble in the absence of a lock
around each update.... and I'd really prefer to avoid such a lock. Are
you suggesting I should use 2 independent seqcounts? One for RX path,
the other for TX path, all this without a lock around writers?
Side-note: what are the bad implications of using atomic_t (in the fast paths)?
next prev parent reply other threads:[~2011-11-16 19:25 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-16 5:15 [PATCH net-next v5 00/10] net-sysfs+forcedeth: stats & debug enhancements David Decotigny
2011-11-16 5:15 ` [PATCH net-next v5 01/10] forcedeth: fix stats on hardware without extended stats support David Decotigny
2011-11-16 5:15 ` [PATCH net-next v5 02/10] net-sysfs: fixed minor sparse warning David Decotigny
2011-11-16 5:15 ` [PATCH net-next v5 03/10] kbuild: document RPS/XPS network Kconfig options David Decotigny
2011-11-16 5:15 ` [PATCH net-next v5 04/10] net: provide counter for tx_timeout errors in sysfs David Decotigny
2011-11-16 16:51 ` Stephen Hemminger
2011-11-16 5:15 ` [PATCH net-next v5 05/10] forcedeth: Add messages to indicate using MSI or MSI-X David Decotigny
2011-11-16 5:15 ` [PATCH net-next v5 06/10] forcedeth: allow to silence "TX timeout" debug messages David Decotigny
2011-11-16 5:15 ` [PATCH net-next v5 07/10] forcedeth: implement ndo_get_stats64() API David Decotigny
2011-11-16 16:55 ` Stephen Hemminger
2011-11-16 17:14 ` Ben Hutchings
2011-11-16 19:25 ` David Decotigny [this message]
2011-11-16 19:32 ` Ben Hutchings
2011-11-16 20:32 ` Eric Dumazet
2011-11-16 20:46 ` David Decotigny
2011-11-16 5:15 ` [PATCH net-next v5 08/10] forcedeth: account for dropped RX frames David Decotigny
2011-11-16 5:15 ` [PATCH net-next v5 09/10] forcedeth: stats updated with a deferrable timer David Decotigny
2011-11-16 5:15 ` [PATCH net-next v5 10/10] forcedeth: whitespace/indentation fixes David Decotigny
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