• Michael Petlan's avatar
    perf header: Fix false warning when there are no duplicate cache entries · 28707826
    Michael Petlan authored
    Before this patch, perf expected that there might be NPROC*4 unique
    cache entries at max, however, it also expected that some of them would
    be shared and/or of the same size, thus the final number of entries
    would be reduced to be lower than NPROC*4. In case the number of entries
    hadn't been reduced (was NPROC*4), the warning was printed.
    
    However, some systems might have unusual cache topology, such as the
    following two-processor KVM guest:
    
    	cpu  level  shared_cpu_list  size
    	  0     1         0           32K
    	  0     1         0           64K
    	  0     2         0           512K
    	  0     3         0           8192K
    	  1     1         1           32K
    	  1     1         1           64K
    	  1     2         1           512K
    	  1     3         1           8192K
    
    This KVM guest has 8 (NPROC*4) unique cache entries, which used to make
    perf printing the message, although there actually aren't "way too many
    cpu caches".
    
    v2: Removing unused argument.
    
    v3: Unifying the way we obtain number of cpus.
    
    v4: Removed '& UINT_MAX' construct which is redundant.
    Signed-off-by: default avatarMichael Petlan <mpetlan@redhat.com>
    Acked-by: default avatarJiri Olsa <jolsa@redhat.com>
    LPU-Reference: 20191208162056.20772-1-mpetlan@redhat.com
    Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
    28707826
header.c 82.7 KB