Date: Fri, 6 Mar 2009 09:25:39 +0000 (GMT) From: Robert Watson <rwatson@FreeBSD.org> To: "Wilkinson, Alex" <alex.wilkinson@dsto.defence.gov.au> Cc: freebsd-current@freebsd.org Subject: Re: pflogd eats 100% cpu now, updated -current from Feb-4 to Mar-4 Message-ID: <alpine.BSF.2.00.0903060924220.40469@fledge.watson.org> In-Reply-To: <20090306002750.GN94275@stlux503.dsto.defence.gov.au> References: <49AFB9DA.7030105@dva.dyndns.org> <20090305230639.GA21057@jnz.sqrt.ca> <20090306002750.GN94275@stlux503.dsto.defence.gov.au>
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On Fri, 6 Mar 2009, Wilkinson, Alex wrote: > 0n Thu, Mar 05, 2009 at 05:06:39PM -0600, Christian Peron wrote: > > >We recently turned on zerocopy so it can see some exposure. I will > >look into this. > > Can anyone explain what this actually means ? > > net.bpf.zerocopy_enable: Enable new zero-copy BPF buffer sessions BPF now supports a shared memory buffering scheme between userspace and kernel; when the sysctl is enabled, newly opened /dev/bpf devices will permit configuration of the zero-copy scheme. The sysctl doesn't turn zero-copy on and off per se, since existing configured sessions will continue to use it, but no new zero-copy sessions will be permitted when the sysctl is disabled. However, it sounds like there's some interaction between pflogd and the zero-copy code that requires some debugging... Robert N M Watson Computer Laboratory University of Cambridge
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