netdev - Re: [net-next PATCH] pktgen: add flag NO_TIMESTAMP to disable timestamping

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Message-ID: <551C2178.9070000@candelatech.com>
Date:	Wed, 01 Apr 2015 09:48:56 -0700
From:	Ben Greear <greearb@...delatech.com>
To:	Jesper Dangaard Brouer <brouer@...hat.com>
CC:	"David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org,
	Robert Olsson <robert@...julf.se>
Subject: Re: [net-next PATCH] pktgen: add flag NO_TIMESTAMP to disable timestamping

On 08/28/2014 09:14 AM, Jesper Dangaard Brouer wrote:
> Then testing the TX limits of the stack, then it is useful to
> be-able to disable the do_gettimeofday() timetamping on every packet.
> 
> This implements a pktgen flag NO_TIMESTAMP which will disable this
> call to do_gettimeofday().
> 
> The performance change on (my system E5-2695) with skb_clone=0, goes
> from TX 2,423,751 pps to 2,567,165 pps with flag NO_TIMESTAMP. Thus,
> the cost of do_gettimeofday() or saving is approx 23 nanosec.
> 
> Signed-off-by: Jesper Dangaard Brouer <brouer@...hat.com>

> +		else if (strcmp(f, "NO_TIMESTAMP") == 0)
> +			pkt_dev->flags |= F_NO_TIMESTAMP;
> +

While porting pktgen changes into my own modified pktgen logic, I noticed
that there is no handling for !NO_TIMESTAMP, so it seems you cannot
disable this once it is enabled?

Thanks,
Ben

-- 
Ben Greear <greearb@...delatech.com>
Candela Technologies Inc  http://www.candelatech.com

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