Date: Tue, 27 Dec 2011 22:32:13 -0800 From: Juli Mallett <jmallett@freebsd.org> To: lev@freebsd.org Cc: Pawel Tyll <ptyll@nitronet.pl>, "Alexander V. Chernikov" <melifaro@freebsd.org>, Luigi Rizzo <rizzo@iet.unipi.it>, freebsd-ipfw@freebsd.org, freebsd-net@freebsd.org Subject: Re: Firewall Profiling. Message-ID: <CACVs6=99=xGhNVBgQhzmm8FFdSf7P-d5zKuyFRm8MMnhAjc-1Q@mail.gmail.com> In-Reply-To: <91777482.20111228102644@serebryakov.spb.ru> References: <1498545030.20111227015431@nitronet.pl> <4EF9ADBC.8090402@FreeBSD.org> <623366116.20111227150047@nitronet.pl> <20111227142600.GA65456@onelab2.iet.unipi.it> <91777482.20111228102644@serebryakov.spb.ru>
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2011/12/27 Lev Serebryakov <lev@freebsd.org>: > Hello, Luigi. > You wrote 27 =D0=B4=D0=B5=D0=BA=D0=B0=D0=B1=D1=80=D1=8F 2011 =D0=B3., 18:= 26:00: > >> plans, yes - not sure how long it will take. I have compiled >> ipfw+dummynet as a standalone module (outside the kernel) >> but have not yet hooked the code to netmap to figure out how fast >> it can run. > =C2=A0I still don't understand why it should be faster than "normal" way, > as it is essentially same (ipfw + dummynet) code + some additional > context switches for netmap (to userland and back). > =C2=A0What does netmap shave off from packet processing in this particula= r > case, to compensate context switches? I Reloading of mbufs into DMA descriptors? mbuf allocator overhead itself? Interrupts. Context switches under constant heavy load. Some indirection in the network stack.
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