43ceb1fb4c
An IPI cannot be sent via the local APIC if a previous IPI is still being delivered. Attempts to send an IPI will wait for a pending IPI to clear. Prior to r278325 these checks used a spin loop with a hardcoded maximum count which broke AP startup on some systems. However, r278325 also enforced a minimum latency of 5 microseconds if an IPI was still pending which resulted in a measurable performance hit. This change reduces that minimum latency to 1 microsecond. Tested by: stas MFC after: 3 days |
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| .. | ||
| acpica | ||
| bios | ||
| cpufreq | ||
| include | ||
| iommu | ||
| isa | ||
| pci | ||
| x86 | ||
| xen | ||