HWLOC-GATHER-TOPOLOGY(1)					       hwloc						  HWLOC-GATHER-TOPOLOGY(1)

NAME

       hwloc-gather-topology - Saves the relevant Linux topology files and the lstopo output for later (possibly offline) usage.

SYNOPSIS

       hwloc-gather-topology [options] <path>

OPTIONS

       -h --help display help message and exit

DESCRIPTION

       hwloc-gather-topology  saves  all  the relevant topology files into an archive (<path>.tar.bz2) and the lstopo output (<path>.output).  The
       utility for example stores the /proc/cpuinfo file and the entire /sys/devices/system/node/ directory tree.

       These files can be used later to explore the machine topology offline.  Once the tarball has been extracted, it may for instance  be  given
       to  some  hwloc	command-line  utilities through their --input option.  It is also possible to override the default topology that the hwloc
       library will read by setting the extracted path in the HWLOC_FSROOT environment variable.

       Both archive and lstopo output may also be submitted to hwloc developers to debug issues remotely.

       hwloc-gather-topology is a Linux specific tool, it is not installed on other operating systems.

       NOTE: It is highly recommended that you read the hwloc(7) overview page before reading this man page.

EXAMPLES

       To store topology information to be used later (possibly on a different host) please run:

	    hwloc-gather-topology /tmp/myhost

       It will store all relevant topology files in the /tmp/myhost.tar.bz2 archive and the lstopo output in the /tmp/myhost.output  file.   These
       files can be transferred on another host for later/offline analysis and/or as the input to various hwloc utilities.

       To use these data with hwloc utilities you have to unpack myhost.tar.bz2 archive first:

	    tar jxvf /tmp/myhost.tar.bz2

       A new directory named myhost now contains all topology files.  Then you ask various hwloc utilities to use this topology instead of the one
       of the real machine by passing --input myhost.  To display the topology just run:

	    lstopo --input ./myhost

       It is not necessary that the topology is extracted in the current directory, absolute or relative paths are also supported:

	    lstopo --input /path/to/remote/host/extracted/topology/

       To see how hwloc would distribute 8 parallel jobs on the original host:

	    hwloc-distrib --input myhost --single 8

       To get the corresponding physical indexes in the previous command:

	    hwloc-calc --input myhost --po --li --proclist $(hwloc-distrib --input myhost --single 8)

       Any program may actually override the default topology with a given archived  one  even	if  it	does  not  have  a  --input  option.   The
       HWLOC_FSROOT environment variable should be used to do so:

	    HWLOC_FSROOT=myhost hwloc-calc --po --li --proclist $(hwloc-distrib --single 8)

       All  these commands will produce the same output as if executed directly on the host on which the topology information was originally gath-
       ered by the hwloc-gather-topology script.

RETURN VALUE

       Upon successful execution, hwloc-gather-topology will exit with the code 0.

       hwloc-gather-topology will return nonzero exit status if any kind of error occurs, such as (but not limited to) failure to create  the  ar-
       chive or output file.

SEE ALSO

       hwloc(7), lstopo(1), hwloc-calc(1), hwloc-distrib(1)

1.4.1								   Feb 27, 2012 					  HWLOC-GATHER-TOPOLOGY(1)