Date: Wed, 13 May 2015 08:04:50 +0000 (UTC) From: Hiren Panchasara <hiren@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-10@freebsd.org Subject: svn commit: r282832 - stable/10/sys/net Message-ID: <201505130804.t4D84oCO021574@svn.freebsd.org>
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Author: hiren Date: Wed May 13 08:04:50 2015 New Revision: 282832 URL: https://svnweb.freebsd.org/changeset/base/282832 Log: MFC r281984: Currently there is no easy way to specify net.isr.maxthreads = all cpus. We need to specify exact number of cpus in loader.conf which get annoying when you have mix of machines which don't have equal number of total cpus. I propose "-1" as that value. When loader.conf has net.isr.maxthreads = -1, netisr will use all available cpus. Sponsored by: Limelight Networks Modified: stable/10/sys/net/netisr.c Directory Properties: stable/10/ (props changed) Modified: stable/10/sys/net/netisr.c ============================================================================== --- stable/10/sys/net/netisr.c Wed May 13 07:39:16 2015 (r282831) +++ stable/10/sys/net/netisr.c Wed May 13 08:04:50 2015 (r282832) @@ -156,10 +156,13 @@ SYSCTL_PROC(_net_isr, OID_AUTO, dispatch /* * Allow the administrator to limit the number of threads (CPUs) to use for * netisr. We don't check netisr_maxthreads before creating the thread for - * CPU 0, so in practice we ignore values <= 1. This must be set at boot. - * We will create at most one thread per CPU. + * CPU 0. This must be set at boot. We will create at most one thread per CPU. + * By default we initialize this to 1 which would assign just 1 cpu (cpu0) and + * therefore only 1 workstream. If set to -1, netisr would use all cpus + * (mp_ncpus) and therefore would have those many workstreams. One workstream + * per thread (CPU). */ -static int netisr_maxthreads = -1; /* Max number of threads. */ +static int netisr_maxthreads = 1; /* Max number of threads. */ TUNABLE_INT("net.isr.maxthreads", &netisr_maxthreads); SYSCTL_INT(_net_isr, OID_AUTO, maxthreads, CTLFLAG_RDTUN, &netisr_maxthreads, 0, @@ -1128,8 +1131,10 @@ netisr_init(void *arg) KASSERT(curcpu == 0, ("%s: not on CPU 0", __func__)); NETISR_LOCK_INIT(); - if (netisr_maxthreads < 1) - netisr_maxthreads = 1; + if (netisr_maxthreads == 0 || netisr_maxthreads < -1 ) + netisr_maxthreads = 1; /* default behavior */ + else if (netisr_maxthreads == -1) + netisr_maxthreads = mp_ncpus; /* use max cpus */ if (netisr_maxthreads > mp_ncpus) { printf("netisr_init: forcing maxthreads from %d to %d\n", netisr_maxthreads, mp_ncpus);
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