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hbruecknerMartin Schwidefsky
hbrueckner
authored and
Martin Schwidefsky
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s390/cpum_sf: Dynamically extend the sampling buffer if overflows occur
Improve the sampling buffer allocation and add a function to reallocate and increase the sampling buffer structure. The number of allocated buffer elements (sample-data-blocks) are accounted. You can control the minimum and maximum number these sample-data-blocks through the cpum_sfb_size kernel parameter. The number hardware sample overflows (if any) are also accounted and stored per perf event. During the PMU disable/enable calls, the accumulated overflow counter is analyzed and, if necessary, the sampling buffer is dynamically increased. Signed-off-by: Hendrik Brueckner <[email protected]> Signed-off-by: Martin Schwidefsky <[email protected]>
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‎arch/s390/include/asm/perf_event.h‎

Lines changed: 4 additions & 0 deletions
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@@ -49,6 +49,10 @@ extern unsigned long perf_misc_flags(struct pt_regs *regs);
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#define PERF_CPUM_SF_MAX_CTR 1
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#define PERF_EVENT_CPUM_SF 0xB0000UL /* Raw event ID */
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#define REG_NONE 0
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#define REG_OVERFLOW 1
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#define OVERFLOW_REG(hwc) ((hwc)->extra_reg.config)
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#define SFB_ALLOC_REG(hwc) ((hwc)->extra_reg.alloc)
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#define TEAR_REG(hwc) ((hwc)->last_tag)
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#define SAMPL_RATE(hwc) ((hwc)->event_base)
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