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This adds workarounds for two hardware bugs in the POWER8 performance monitor unit (PMU), both related to interrupt generation. The effect of these bugs is that PMU interrupts can get lost, leading to tools such as perf reporting fewer counts and samples than they should. The first bug relates to the PMAO (perf. mon. alert occurred) bit in MMCR0; setting it should cause an interrupt, but doesn't. The other bug relates to the PMAE (perf. mon. alert enable) bit in MMCR0. Setting PMAE when a counter is negative and counter negative conditions are enabled to cause alerts should cause an alert, but doesn't. The workaround for the first bug is to create conditions where a counter will overflow, whenever we are about to restore a MMCR0 value that has PMAO set (and PMAO_SYNC clear). The workaround for the second bug is to freeze all counters using MMCR2 before reading MMCR0. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de> |
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| .. | ||
| boot | ||
| configs | ||
| crypto | ||
| include | ||
| kernel | ||
| kvm | ||
| lib | ||
| math-emu | ||
| mm | ||
| net | ||
| oprofile | ||
| perf | ||
| platforms | ||
| sysdev | ||
| xmon | ||
| Kconfig | ||
| Kconfig.debug | ||
| Makefile | ||
| relocs_check.pl | ||