Wireshark-dev: Re: [Wireshark-dev] Enabling linux kernel jit compiler from dumpcap?
-----Original Message-----
From: wireshark-dev-bounces@xxxxxxxxxxxxx [mailto:wireshark-dev-bounces@xxxxxxxxxxxxx] On Behalf Of Bálint Réczey
Sent: den 23 augusti 2013 12:59
To: Developer support list for Wireshark
Subject: Re: [Wireshark-dev] Enabling linux kernel jit compiler from dumpcap?
2013/8/23 Anders Broman <anders.broman@xxxxxxxxxxxx>:
>> before we change it, should we remember the previous setting and restore it when dumpcap exits?
>
> Preferably yes but I'm not sure it's possible as I think root
> privileges are required to write to the file and I think dumpcap Drops those after starting to capture.
And in the configuration the documentation recommends dumpcap does not run as root, it has permission to capture only.
Cheers,
Balint
That's kind of my point after all these years this is still not used by every one.
>
> Regards
> Anders
>
> -----Original Message-----
> From: wireshark-dev-bounces@xxxxxxxxxxxxx
> [mailto:wireshark-dev-bounces@xxxxxxxxxxxxx] On Behalf Of Martin
> Kaiser
> Sent: den 23 augusti 2013 10:36
> To: wireshark-dev@xxxxxxxxxxxxx
> Subject: Re: [Wireshark-dev] Enabling linux kernel jit compiler from dumpcap?
>
> before we change it, should we remember the previous setting and restore it when dumpcap exits?
>
> Thus wrote Anders Broman (a.broman@xxxxxxxxxxxx):
>
>> Bálint Réczey skrev 2013-08-22 23:02:
>>> Hi,
>
>>> I would be happier if the applications I run did not change kernel
>>> configuration without my consent.
>> I see your point...
>
>>> Regarding Wireshark I would prefer suggesting "echo 1 >
>>> /proc/sys/net/core/bpf_jit_enable" in the documentation instead of
>>> adding code to enable JIT.
>>> There may be good reasons for not enabling it by default in the Linux kernel.
>> The problematic thing is that people seldom reads the documentation,
>> the setting gets reset at a reboot and it's easy to forget to
>> re-enable it. The ideal thing would be if dumpcap
>> - Had a preference/command line flag whether to use JIT or not.
>> - If told to use it check if it was enabled or not used JIT and put
>> it back to zero if not set when starting.
>> Wireshark could then default to use JIT and some warnings could be
>> displayed in the welcome screen and in dumpcaps help output.
>
>> netsniff-ng activates it by default it seems.
>> Regards
>> Anders
>
>>> Cheers,
>>> Balint
>
>>> 2013/8/22 Anders Broman <a.broman@xxxxxxxxxxxx>:
>>>> Guy Harris skrev 2013-08-22 18:16:
>
>>>>> On Aug 22, 2013, at 4:46 AM, Anders Broman
>>>>> <anders.broman@xxxxxxxxxxxx>
>>>>> wrote:
>
>>>>>> Should we add code to enable the JIT compiler from dumpcap?
>>>>> Should I add code to enable the JIT compiler to libpcap while I'm at it?
>
>>>>> Should the Linux kernel folks enable it by default?
>
>>>>> I'm inclined to answer "yes" to all three questions. I think the
>>>>> FreeBSD JIT compiler is enabled by default. I'm surprised that the Linux one isn't.
>>>> I checked in the dumpcap code. I agree that it might be useful in
>>>> libpcap too, root privileges are required to change it I think. and
>>>> Yes
>
>>>>> I'm surprised that the Linux one isn't
>>>> Regards
>>>> Anders
>
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