Date: Thu, 28 Jun 2012 10:25:38 +0800 From: David Xu <listlog2011@gmail.com> To: Attilio Rao <attilio@freebsd.org> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org, Konstantin Belousov <kib@freebsd.org>, davidxu@freebsd.org Subject: Re: svn commit: r237660 - head/lib/libc/gen Message-ID: <4FEBC0A2.3010708@gmail.com> In-Reply-To: <CAJ-FndBdpP4hFPyqHaU6GucXeGi3WT4d%2Bpu-9hCNEpAPZAZQgg@mail.gmail.com> References: <201206272032.q5RKWjvt031174@svn.freebsd.org> <4FEBB8C9.8070006@gmail.com> <CAJ-FndBdpP4hFPyqHaU6GucXeGi3WT4d%2Bpu-9hCNEpAPZAZQgg@mail.gmail.com>
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On 2012/6/28 10:21, Attilio Rao wrote: > 2012/6/28, David Xu<listlog2011@gmail.com>: >> On 2012/6/28 4:32, Konstantin Belousov wrote: >>> Author: kib >>> Date: Wed Jun 27 20:32:45 2012 >>> New Revision: 237660 >>> URL: http://svn.freebsd.org/changeset/base/237660 >>> >>> Log: >>> Optimize the handling of SC_NPROCESSORS_CONF, by using auxv AT_NCPU >>> value if present. >>> >>> MFC after: 1 week >>> >>> Modified: >>> head/lib/libc/gen/sysconf.c >>> >>> Modified: head/lib/libc/gen/sysconf.c >>> ============================================================================== >>> --- head/lib/libc/gen/sysconf.c Wed Jun 27 20:24:25 2012 (r237659) >>> +++ head/lib/libc/gen/sysconf.c Wed Jun 27 20:32:45 2012 (r237660) >>> @@ -42,6 +42,7 @@ __FBSDID("$FreeBSD$"); >>> #include<sys/resource.h> >>> #include<sys/socket.h> >>> >>> +#include<elf.h> >>> #include<errno.h> >>> #include<limits.h> >>> #include<paths.h> >>> @@ -51,6 +52,7 @@ __FBSDID("$FreeBSD$"); >>> >>> #include "../stdlib/atexit.h" >>> #include "tzfile.h" /* from ../../../contrib/tzcode/stdtime */ >>> +#include "libc_private.h" >>> >>> #define _PATH_ZONEINFO TZDIR /* from tzfile.h */ >>> >>> @@ -585,6 +587,8 @@ yesno: >>> >>> case _SC_NPROCESSORS_CONF: >>> case _SC_NPROCESSORS_ONLN: >>> + if (_elf_aux_info(AT_NCPUS,&value, sizeof(value)) == 0) >>> + return ((long)value); >>> mib[0] = CTL_HW; >>> mib[1] = HW_NCPU; >>> break; >>> >> Will this make controlling the number of CPU online or CPU hotplug >> be impossible on FreeBSD ? > If I think about hotplug CPUs I can think of other 1000 > problems/races/bad situations to be fixed before this one, really. These are problems only in kernel, but kib's change is about ABI between userland and kernel, I hope we don't introduce an ABI which is not extendable road stone. > Attilio > >
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