netdev - Re: [PATCH net-next] pktgen: Add NOINIT option to leave packet data uninitialized

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Message-ID: <53761286.2040505@candelatech.com>
Date:	Fri, 16 May 2014 06:28:38 -0700
From:	Ben Greear <greearb@...delatech.com>
To:	Eric Dumazet <eric.dumazet@...il.com>, Thomas Graf <tgraf@...g.ch>
CC:	davem@...emloft.net, netdev@...r.kernel.org
Subject: Re: [PATCH net-next] pktgen: Add NOINIT option to leave packet data
 uninitialized



On 05/16/2014 06:16 AM, Eric Dumazet wrote:
> On Fri, 2014-05-16 at 12:34 +0200, Thomas Graf wrote:
>> The memset() on the packet data is expensive and severely limiting
>> the pps throughput for large frame sizes.
>>
>> Considering that pktgen requires root privileges to run it is safe
>> to introduce an option to optionally avoid the memset() and leave
>> the packet data uninitialized.
>>
>> VM test results, 2 VCPU, 2 threads, pkt_size=9K:
>>
>>      12.44%  -11.15%  [kernel.kallsyms]   [k] memset
>>       4.84%   +1.58%  [kernel.kallsyms]   [k] get_page_from_freelist
>>
>> Signed-off-by: Thomas Graf <tgraf@...g.ch>
>> ---
>>   Documentation/networking/pktgen.txt |  3 +++
>>   net/core/pktgen.c                   | 16 ++++++++++++++--
>>   2 files changed, 17 insertions(+), 2 deletions(-)
>
> We do not want to leak content of memory, even if 'root' is willing to.
>
> Sorry, you need to do something else if you really care.

Is there currently no other way for root to grab memory contents and
send them over the network?

I mean, it could load it's own module and do bad things if nothing else?

Thanks,
Ben

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