• Yunlong Song's avatar
    perf kvm: Support using -f to override perf.data.guest file ownership · 8cc5ec1f
    Yunlong Song authored
    Enable perf kvm to use perf.data.guest when it is not owned by current
    user or root.
    
    Example:
    
     # perf kvm stat record ls
     # chown Yunlong.Song:Yunlong.Song perf.data.guest
     # ls -al perf.data.guest
     -rw------- 1 Yunlong.Song Yunlong.Song 4128937 Apr  2 11:05 perf.data.guest
     # id
     uid=0(root) gid=0(root) groups=0(root),64(pkcs11)
    
    Before this patch:
    
     # perf kvm stat report
     File perf.data.guest not owned by current user or root (use -f to override)
     Initializing perf session failed
     # perf kvm stat report -f
       Error: unknown switch `f'
    
      usage: perf kvm stat report [<options>]
    
             --event <report event>
                               event for reporting: vmexit, mmio (x86 only),
                               ioport (x86 only)
             --vcpu <n>        vcpu id to report
         -k, --key <sort-key>  key for sorting: sample(sort by samples
     						   number) time (sort by avg time)
         -p, --pid <pid>       analyze events only for given process id(s)
    
    As shown above, the -f option does not work at all.
    
    After this patch:
    
     # perf kvm stat report
     File perf.data.guest not owned by current user or root (use -f to override)
     Initializing perf session failed
     # perf kvm stat report -f
     Analyze events for all VMs, all VCPUs:
    
       VM-EXIT    Samples  Samples%     Time%    Min Time    Max Time   Avg time
    
     Total Samples:0, Total events handled time:0.00us.
    
    As shown above, the -f option really works now. Since we have not
    launched any KVM related process, the result shows 0 sample here.
    Signed-off-by: default avatarYunlong Song <yunlong.song@huawei.com>
    Tested-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
    Cc: Paul Mackerras <paulus@samba.org>
    Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
    Cc: Wang Nan <wangnan0@huawei.com>
    Link: http://lkml.kernel.org/r/1427982439-27388-5-git-send-email-yunlong.song@huawei.comSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
    8cc5ec1f
builtin-kvm.c 36.6 KB