On Wed, 31 Mar 2021 16:45:05 +0200, Cédric Le Goater wrote:
ipistorm [*] can be used to benchmark the raw interrupt rate of an
interrupt controller by measuring the number of IPIs a system can
sustain. When applied to the XIVE interrupt controller of POWER9 and
POWER10 systems, a significant drop of the interrupt rate can be
observed when crossing the second node boundary.
This is due to the fact that a single IPI interrupt is used for all
CPUs of the system. The structure is shared and the cache line updates
impact greatly the traffic between nodes and the overall IPI
performance.
[...]
Patches 2-9 applied to powerpc/next.
[2/9] powerpc/xive: Introduce an IPI interrupt domain
https://git.kernel.org/powerpc/c/7d348494136c8b47c39d1f7ccba28c47d5094a54
[3/9] powerpc/xive: Remove useless check on XIVE_IPI_HW_IRQ
https://git.kernel.org/powerpc/c/1835e72942b5aa779c8ada62aaeba03ab66d92c9
[4/9] powerpc/xive: Simplify xive_core_debug_show()
https://git.kernel.org/powerpc/c/5159d9872823230669b7949ba3caf18c4c314846
[5/9] powerpc/xive: Drop check on irq_data in xive_core_debug_show()
https://git.kernel.org/powerpc/c/a74ce5926b20cd0e6d624a9b2527073a96dfed7f
[6/9] powerpc/xive: Simplify the dump of XIVE interrupts under xmon
https://git.kernel.org/powerpc/c/6bf66eb8f404050030805c65cf39a810892f5f8e
[7/9] powerpc/xive: Fix xmon command "dxi"
https://git.kernel.org/powerpc/c/33e4bc5946432a4ac173fd08e8e30a13ab94d06d
[8/9] powerpc/xive: Map one IPI interrupt per node
https://git.kernel.org/powerpc/c/7dcc37b3eff97379b194adb17eb9a8270512dd1d
[9/9] powerpc/xive: Modernize XIVE-IPI domain with an 'alloc' handler
https://git.kernel.org/powerpc/c/fd6db2892ebaa1383a93b4a609c65b96e615510a
cheers