[PATCH 09/15] perf kvm: Support using -f to override perf.data.guest file ownership

From: Arnaldo Carvalho de Melo
Date: Thu Apr 02 2015 - 18:29:52 EST


From: Yunlong Song <yunlong.song@xxxxxxxxxx>

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: Yunlong Song <yunlong.song@xxxxxxxxxx>
Tested-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Wang Nan <wangnan0@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/1427982439-27388-5-git-send-email-yunlong.song@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/builtin-kvm.c | 2 ++
tools/perf/util/kvm-stat.h | 1 +
2 files changed, 3 insertions(+)

diff --git a/tools/perf/builtin-kvm.c b/tools/perf/builtin-kvm.c
index 643722f40075..1f9338f6109c 100644
--- a/tools/perf/builtin-kvm.c
+++ b/tools/perf/builtin-kvm.c
@@ -1047,6 +1047,7 @@ static int read_events(struct perf_kvm_stat *kvm)
struct perf_data_file file = {
.path = kvm->file_name,
.mode = PERF_DATA_MODE_READ,
+ .force = kvm->force,
};

kvm->tool = eops;
@@ -1204,6 +1205,7 @@ kvm_events_report(struct perf_kvm_stat *kvm, int argc, const char **argv)
" time (sort by avg time)"),
OPT_STRING('p', "pid", &kvm->opts.target.pid, "pid",
"analyze events only for given process id(s)"),
+ OPT_BOOLEAN('f', "force", &kvm->force, "don't complain, do it"),
OPT_END()
};

diff --git a/tools/perf/util/kvm-stat.h b/tools/perf/util/kvm-stat.h
index cf1d7913783b..ae825d4ec110 100644
--- a/tools/perf/util/kvm-stat.h
+++ b/tools/perf/util/kvm-stat.h
@@ -99,6 +99,7 @@ struct perf_kvm_stat {
int timerfd;
unsigned int display_time;
bool live;
+ bool force;
};

struct kvm_reg_events_ops {
--
1.9.3

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