it's the output, not ack coalescing (Re: TSO and FreeBSD vs Linux)

[Luigi Rizzo]

the usenix paper and talk
https://www.usenix.org/conference/usenixfederatedconferencesweek/netmap-novel-framework-fast-packet-io
should give a short description of what i did.

Basically i manually insert returns (and free mbufs and resources)
in some place in the path and then compute the time consumed by
the code as the inverse of the average pps over 0.1 .. 1s intervals.
By moving the point where i place the return, i can estimate the
cost of the various sections of code involved.

cheers
luigi



On Fri, Aug 16, 2013 at 6:59 PM, Adrian Chadd <adrian at freebsd.org> wrote:

> Luigi,
>
> Did you ever publish your patches or methodology for doing sampling?
>
>
>
> -adrian
>
>
> On 14 August 2013 21:00, Vijay Singh <vijju.singh at gmail.com> wrote:
>
>> Is that what FLOWTABLE does? Also we need a mechanism to record time
>> spent at various layers in the stack. Luigi has used his own methods but
>> we're lacking something more generic. At work we have some crude tools that
>> use mcount information to indirectly measure costs but they are not
>> reliable and only provide partial information.
>>
>> Sent from my iPhone
>>
>> On Aug 14, 2013, at 11:11 AM, Adrian Chadd <adrian at freebsd.org> wrote:
>>
>> > On 14 August 2013 04:47, Lev Serebryakov <lev at freebsd.org> wrote:
>> >
>> >
>> >>  And we should invalidate this info on ARP/route changes, or connection
>> >> will be lost in such cases, am I right?.. So, on each such event code
>> >> should look into all sockets and check, if routing/ARP information is
>> >> still
>> >> valid for them. Or we should store lists of sockets in routing and ARP
>> >> tables... I don't know, what is worse.
>> >
>> > .. or per-CPU copies of the ARP table.. ?
>> >
>> >
>> >
>> > -adrian
>> > _______________________________________________
>> > freebsd-net at freebsd.org mailing list
>> > http://lists.freebsd.org/mailman/listinfo/freebsd-net
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>>
>
>


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