From: Eliezer Tamir <eliezer.tamir@linux.intel.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: David Miller <davem@davemloft.net>,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
Jesse Brandeburg <jesse.brandeburg@intel.com>,
Don Skidmore <donald.c.skidmore@intel.com>,
e1000-devel@lists.sourceforge.net,
Willem de Bruijn <willemb@google.com>,
Andi Kleen <andi@firstfloor.org>, HPA <hpa@zytor.com>,
Eilon Greenstien <eilong@broadcom.com>,
Or Gerlitz <or.gerlitz@gmail.com>,
Alex Rosenbaum <alexr@mellanox.com>,
Eliezer Tamir <eliezer@tamir.org.il>
Subject: Re: [PATCH v6 net-next 2/5] net: implement support for low latency socket polling
Date: Wed, 29 May 2013 17:01:38 +0300 [thread overview]
Message-ID: <51A60A42.20905@linux.intel.com> (raw)
In-Reply-To: <1369834647.5109.15.camel@edumazet-glaptop>
On 29/05/2013 16:37, Eric Dumazet wrote:
> On Wed, 2013-05-29 at 09:39 +0300, Eliezer Tamir wrote:
>> +static inline unsigned long ll_end_time(void)
>> +{
>> + return TSC_MHZ * ACCESS_ONCE(sysctl_net_ll_poll) + get_cycles();
>> +}
>
> This can overflow.
>
> Multiply is giving 32bits, as tsc_khz is an int, and sysctl_net_ll_poll
> is an int.
>
> unsigned long sysctl_net_ll_poll ?
OK
> Also, if we want this to work on i386, the correct type to use for
> ll_end_time(void) would be cycles_t
OK
I would be really surprised if someone uses this on an i386, but I guess
you never know.
Thanks!
-Eliezer
next prev parent reply other threads:[~2013-05-29 14:02 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-29 6:39 [PATCH v6 net-next 0/5] net: low latency Ethernet device polling Eliezer Tamir
2013-05-29 6:39 ` [PATCH v6 net-next 1/5] net: add napi_id and hash Eliezer Tamir
2013-05-29 12:56 ` Eric Dumazet
2013-05-29 13:09 ` David Laight
2013-05-29 13:43 ` Eric Dumazet
2013-05-29 15:04 ` Eliezer Tamir
2013-05-29 20:09 ` Ben Hutchings
2013-05-30 6:51 ` Eliezer Tamir
2013-05-29 6:39 ` [PATCH v6 net-next 2/5] net: implement support for low latency socket polling Eliezer Tamir
2013-05-29 13:37 ` Eric Dumazet
2013-05-29 13:42 ` David Laight
2013-05-29 13:48 ` Eric Dumazet
2013-05-29 14:01 ` Eliezer Tamir [this message]
[not found] ` <CALuTh9EvzhDaqnVV35wytNg6kJhm+HbOjp5tdxWS9bCTVM5YSA@mail.gmail.com>
2013-05-29 15:01 ` Eliezer Tamir
2013-05-29 14:14 ` Or Gerlitz
2013-05-29 14:40 ` yaniv saar
2013-05-29 14:59 ` Eliezer Tamir
2013-05-29 18:52 ` Or Gerlitz
2013-05-29 19:08 ` Eric Dumazet
2013-05-30 5:58 ` Eliezer Tamir
2013-05-30 6:04 ` Eliezer Tamir
2013-05-29 20:20 ` Ben Hutchings
2013-05-29 6:39 ` [PATCH v6 net-next 3/5] tcp: add TCP support for low latency receive poll Eliezer Tamir
2013-05-29 13:38 ` Eric Dumazet
2013-05-29 6:39 ` [PATCH v6 net-next 4/5] ixgbe: Add support for ndo_ll_poll Eliezer Tamir
2013-05-29 6:40 ` [PATCH v6 net-next 5/5] ixgbe: add extra stats " Eliezer Tamir
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=51A60A42.20905@linux.intel.com \
--to=eliezer.tamir@linux.intel.com \
--cc=alexr@mellanox.com \
--cc=andi@firstfloor.org \
--cc=davem@davemloft.net \
--cc=donald.c.skidmore@intel.com \
--cc=e1000-devel@lists.sourceforge.net \
--cc=eilong@broadcom.com \
--cc=eliezer@tamir.org.il \
--cc=eric.dumazet@gmail.com \
--cc=hpa@zytor.com \
--cc=jesse.brandeburg@intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=or.gerlitz@gmail.com \
--cc=willemb@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).