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  • Hendrik Brueckner's avatar
    s390/cpum_sf: Add flag to process full SDBs only · d7528862
    Hendrik Brueckner authored
    
    
    Add the PERF_CPUM_SF_FULL_BLOCKS flag to process only sample-data-blocks that
    have the block-full-indicator bit set.  Sample-data-blocks that are partially
    filled are discarded.  Use this flag if the sampling buffer is likely to be
    shared among perf events that use different sampling modes.  In such
    environments, flushing sample-data-blocks that are not completely filled, might
    cause invalid-data-formats.
    
    Setting PERF_CPUM_SF_FULL_BLOCKS prevents potentially invalid sampling data to
    be processed but, in contrast, also discards valid samples in partially filled
    sample-data-blocks.  Note that sample-data-blocks might not become full for
    small sampling frequencies or for workload that is scheduled for tiny intervals.
    
    To sample with the PERF_CPUM_SF_FULL_BLOCKS flag, set the perf->attr.config1
    to 0x0004.  For example:
    
    	perf record -e cpum_sf/config=0xB000,config1=0x0004/
    
    Signed-off-by: default avatarHendrik Brueckner <brueckner@linux.vnet.ibm.com>
    Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
    d7528862