Concurrent Technologies RCIM I, Руководство пользователя

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RCIM User’s Guide
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General Considerations
1
When configuring the RCIM systems, keep the following in mind:
•
For a chain of RCIMs, the tick clock and POSIX clock in all slave RCIMs
will be synchronized with the master because the clock signal incrementing
time in the master is broadcast to all slaves. Once the clocks on all RCIMs
are initially syncronized they will remain synchronized.
To synchronize tick clocks, a working TCP/IP connection between all
systems is needed. In addition, each slave RCIM hostname configuration
must be set to the master RCIM, and each slave must be configured to run
the
rcim_clocksync
init script once on boot. This is only required if
your application is using the tick clock for synchronization.
ntp
can be used to synchronize the POSIX clocks, however for the RCIM-
III there is a better mechanism:
rcimdate
(8). The RCIM-III master
broadcasts its POSIX time down the RCIM cabling once per second;
rcimdate
uses this to make the slave POSIX clocks exactly match the
master. This has several advantages over
ntp
: no TCP/IP connections
b e t w e e n s y s t e m s a r e r e q u i r e d , s y n c h r o n i z a t i o n i s fa s t e r, a n d
synchronization is extremely accurate.
•
Interrupts, whether operating locally or distributed across an RCIM chain,
will be processed according to the values configured on each system. If you
wish them to function in a manner different from established defaults, the
desired configuration options must be specified.
•
When distributing interrupts across the systems in an RCIM chain, all
systems must have a compatible configuration for the distributed interrupt
lines.
MSI Interrupt Configuration
1
The latest version of RCIM III (revision 9 and later) supports MSI (message signaled
interrupts). By default, the RCIM kernel driver will initialize the hardware to use MSI
interrupts instead of PCI INTA interrupts whenever possible. By using MSI interrupts, the
RCIM III is guaranteed of having its own non-shared interrupt, thus providing more
reliable interrupt response times.
The RCIM driver has an
rcim.nomsi=1
option which is independent of the
rcim=
configuration option described earlier. All versions of the driver have this option. If
specified the MSI capability is disabled on all RCIM boards that support it. There is no
mechanism to pick which boards are to be MSI-disabled and which ones are not. When
this option is specified, the RCIM driver will fallback to using the PCI INTA interrupt
method. For perfomance reasons, this option should only be used if a problem with MSI
interrupts is encountered.
For a statically linked RCIM driver, this tunable can be specified on the GRUB boot
loader command line (
rcim.nomsi=1
). For an RCIM in module form, this tunable can
be placed in
/etc/modprobe.conf
as “
options rcim.nomsi=1
”.
This option has no effect on RCIM II or RCIM I systems.
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