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Date:      Mon, 30 Mar 2015 18:20:45 +0200 (CEST)
From:      Emeric POUPON <emeric.poupon@stormshield.eu>
To:        Gleb Smirnoff <glebius@FreeBSD.org>
Cc:        Hans Petter Selasky <hps@selasky.org>, Adrian Chadd <adrian@freebsd.org>, src-committers@freebsd.org, Ian Lepore <ian@freebsd.org>, svn-src-all@freebsd.org, Slawa Olhovchenkov <slw@zxy.spb.ru>, svn-src-head@freebsd.org, Fabien Thomas <fabient@freebsd.org>
Subject:   Re: svn commit: r280759 - head/sys/netinet
Message-ID:  <964618150.26750606.1427732445799.JavaMail.zimbra@stormshield.eu>
In-Reply-To: <20150330152707.GP64665@FreeBSD.org>
References:  <20150329210757.GA64665@FreeBSD.org> <551943B4.90102@selasky.org> <20150330125115.GI64665@FreeBSD.org> <551948A4.1070408@selasky.org> <5519535C.40608@selasky.org> <20150330141616.GC74532@zxy.spb.ru> <1872802434.26738716.1427729028579.JavaMail.zimbra@stormshield.eu> <20150330152707.GP64665@FreeBSD.org>

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Yes, sure!

I will test it tomorrow and tell you the results.
However, keep in mind I did not see any performance impact with the previou=
s patch.

Regards,

----- Mail original -----
De: "Gleb Smirnoff" <glebius@FreeBSD.org>
=C3=80: "Emeric POUPON" <emeric.poupon@stormshield.eu>
Cc: "Slawa Olhovchenkov" <slw@zxy.spb.ru>, "Hans Petter Selasky" <hps@selas=
ky.org>, "Adrian Chadd" <adrian@freebsd.org>, src-committers@freebsd.org, "=
Ian Lepore" <ian@freebsd.org>, svn-src-all@freebsd.org, svn-src-head@freebs=
d.org, "Fabien Thomas" <fabient@freebsd.org>
Envoy=C3=A9: Lundi 30 Mars 2015 17:27:07
Objet: Re: svn commit: r280759 - head/sys/netinet

On Mon, Mar 30, 2015 at 05:23:48PM +0200, Emeric POUPON wrote:
E> Hello,
E>=20
E> Sorry for late response, I didn't notice this issue was discussed here.
E>=20
E> In one of our tests, we have several (up to 12) cpu that emit packets wi=
th the same src, dst and protocol to a remote host.
E> We did this patch since we observed bad packet reassembly on the remote =
host, due to different fragments emitted with the same ip id.
E> It was an IPsec test (emitting ESP packets) but I guess we could easily =
reproduce this problem using several "ping -i 0 -s BIG_SIZE_HERE DST" comma=
nds running in parallel.
E>=20
E> Even if we reached something like 1M pps, it is likely that we did not s=
ee any performance penalty since the IPsec stack is quite time consuming.
E> Now, the question is: is there a real performance issue here or is it li=
kely to be hidden by other problems?
E>=20
E> If it is a real problem, maybe an acceptable tradeoff would be to make t=
he counter per CPU and:
E> - initialize it with the cpu id,
E> - increment it by the number of cpus.
E>=20
E> What do you think?

I already posted a patch that makes the counter per CPU. Can you please tes=
t it?

--=20
Totus tuus, Glebius.



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