Date: Tue, 11 Mar 2008 14:31:20 GMT From: Robert Watson <rwatson@FreeBSD.org> To: Perforce Change Reviews <perforce@freebsd.org> Subject: PERFORCE change 137397 for review Message-ID: <200803111431.m2BEVK64037316@repoman.freebsd.org>
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http://perforce.freebsd.org/chv.cgi?CH=137397 Change 137397 by rwatson@rwatson_cinnamon on 2008/03/11 14:30:41 A bit more detail on the shared memory model and a pointer to bpf(4). Affected files ... .. //depot/projects/zcopybpf/src/sys/net/bpf_zerocopy.c#29 edit Differences ... ==== //depot/projects/zcopybpf/src/sys/net/bpf_zerocopy.c#29 (text+ko) ==== @@ -60,7 +60,11 @@ * are mapped into the kernel address space using sf_bufs and used directly * by BPF. Memory is wired since page faults cannot be tolerated in the * contexts where the buffers are copied to (locks held, interrupt context, - * etc). + * etc). Access to shared memory buffers is synchronized using a header on + * each buffer, allowing the number of system calls to go to zero as BPF + * reaches saturation (buffers filled as fast as they can be drained by the + * user process). Full details of the protocol for communicating between the + * user process and BPF may be found in bpf(4). */ /*
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