HWLOC-GATHER-TOPOLOGY(1) hwloc HWLOC-GATHER-TOPOLOGY(1)NAMEhwloc-gather-topology - Saves the relevant Linux topology files and the
lstopo output for later (possibly offline) usage.
SYNOPSIShwloc-gather-topology [options] <path>
OPTIONS-h --help display help message and exit
DESCRIPTIONhwloc-gather-topology saves all the relevant topology files into an ar‐
chive (<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 develop‐
ers 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-dis‐
trib --single 8)
All these commands will produce the same output as if executed directly
on the host on which the topology information was originally gathered
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 ALSOhwloc(7), lstopo(1), hwloc-calc(1), hwloc-distrib(1)1.5 Jul 30, 2012 HWLOC-GATHER-TOPOLOGY(1)
