netdev
[Top] [All Lists]

Re: gettime: Was (Re: Route cache performance under stress

To: Jamal Hadi <hadi@xxxxxxxxxxxxxxxx>
Subject: Re: gettime: Was (Re: Route cache performance under stress
From: Ben Greear <greearb@xxxxxxxxxxxxxxx>
Date: Wed, 11 Jun 2003 08:57:24 -0700
Cc: "David S. Miller" <davem@xxxxxxxxxx>, netdev@xxxxxxxxxxx
In-reply-to: <20030611065255.L39678@xxxxxxxxxxxxxxxx>
Organization: Candela Technologies
References: <3EE682B8.8060708@xxxxxxxxxxxxxxx> <20030610.182234.74725315.davem@xxxxxxxxxx> <3EE68B15.60802@xxxxxxxxxxxxxxx> <20030610.203325.41658167.davem@xxxxxxxxxx> <20030611065255.L39678@xxxxxxxxxxxxxxxx>
Sender: netdev-bounce@xxxxxxxxxxx
User-agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4) Gecko/20030529
Jamal Hadi wrote:
Ok, time to go into another separate thread ;->

Sounds like a good idea.

if (skbneedstimestamp)
        do_gettimeofday(&skb->stamp);
else
        defertimestamp()

For defertimestamp() would it be feasible that you store only the
jiffies value in the skb then get timeofday later and somehow
compensate for the difference? Seems very doable to me.

Question is when do you decide skbneedstimestamp?
Is it when the device is in promiscous mode or do it in ip or icmp etc?

cheers,
jamal

Jiffies is not nearly precise enough.  You need something with
usec precision at least.

If we make a macro to read the value (converting as needed), and just
change all the readers to use that macro, then we don't have to make any
interesting decisions in the networking core.

Ben


--
Ben Greear <greearb@xxxxxxxxxxxxxxx>       <Ben_Greear AT excite.com>
President of Candela Technologies Inc      http://www.candelatech.com
ScryMUD:  http://scry.wanfear.com     http://scry.wanfear.com/~greear



<Prev in Thread] Current Thread [Next in Thread>