Re: [PATCH v2 6/8] perf mmap: Fix perf backward recording

2017-12-04 Thread Arnaldo Carvalho de Melo 
Em Mon, Dec 04, 2017 at 02:37:44PM +0900, Namhyung Kim escreveu:
> Hi,
> 
> On Sun, Dec 03, 2017 at 02:00:42AM +, Wang Nan wrote:
> > perf record backward recording doesn't work as we expected: it never
> > overwrite when ring buffer full.
> > 
> > Test:
> > 
> > (Run a busy printing task background like this:
> > 
> >  while True:
> >  print 123
> > 
> > send SIGUSR2 to perf to capture snapshot.)
> > 
> >  # ./perf record --overwrite -e raw_syscalls:sys_enter -e 
> > raw_syscalls:sys_exit --exclude-perf -a --switch-output
> >  [ perf record: dump data: Woken up 1 times ]
> >  [ perf record: Dump perf.data.2017110101520743 ]
> >  [ perf record: dump data: Woken up 1 times ]
> >  [ perf record: Dump perf.data.2017110101521251 ]
> >  [ perf record: dump data: Woken up 1 times ]
> >  [ perf record: Dump perf.data.2017110101521692 ]
> >  ^C[ perf record: Woken up 1 times to write data ]
> >  [ perf record: Dump perf.data.2017110101521936 ]
> >  [ perf record: Captured and wrote 0.826 MB perf.data. ]
> > 
> >  # ./perf script -i ./perf.data.2017110101520743 | head -n3
> >  perf  2717 [000] 12449.310785: raw_syscalls:sys_enter: NR 16 
> > (5, 2400, 0, 59, 100, 0)
> >  perf  2717 [000] 12449.310790: raw_syscalls:sys_enter: NR 7 
> > (4112340, 2, , 3df, 100, 0)
> >python  2545 [000] 12449.310800:  raw_syscalls:sys_exit: NR 1 = 4
> >  # ./perf script -i ./perf.data.2017110101521251 | head -n3
> >  perf  2717 [000] 12449.310785: raw_syscalls:sys_enter: NR 16 
> > (5, 2400, 0, 59, 100, 0)
> >  perf  2717 [000] 12449.310790: raw_syscalls:sys_enter: NR 7 
> > (4112340, 2, , 3df, 100, 0)
> >python  2545 [000] 12449.310800:  raw_syscalls:sys_exit: NR 1 = 4
> >  # ./perf script -i ./perf.data.2017110101521692 | head -n3
> >  perf  2717 [000] 12449.310785: raw_syscalls:sys_enter: NR 16 
> > (5, 2400, 0, 59, 100, 0)
> >  perf  2717 [000] 12449.310790: raw_syscalls:sys_enter: NR 7 
> > (4112340, 2, , 3df, 100, 0)
> >python  2545 [000] 12449.310800:  raw_syscalls:sys_exit: NR 1 = 4
> > 
> > Timestamps are never change, but my background task is a dead loop, can
> > easily overwhelme the ring buffer.
> > 
> > This patch fix it by force unsetting PROT_WRITE for backward ring
> > buffer, so all backward ring buffer become overwrite ring buffer.
> > 
> > Test result:
> > 
> >  # ./perf record --overwrite -e raw_syscalls:sys_enter -e 
> > raw_syscalls:sys_exit --exclude-perf -a --switch-output
> >  [ perf record: dump data: Woken up 1 times ]
> >  [ perf record: Dump perf.data.2017110101285323 ]
> >  [ perf record: dump data: Woken up 1 times ]
> >  [ perf record: Dump perf.data.2017110101290053 ]
> >  [ perf record: dump data: Woken up 1 times ]
> >  [ perf record: Dump perf.data.2017110101290446 ]
> >  ^C[ perf record: Woken up 1 times to write data ]
> >  [ perf record: Dump perf.data.2017110101290837 ]
> >  [ perf record: Captured and wrote 0.826 MB perf.data. ]
> >  # ./perf script -i ./perf.data.2017110101285323 | head -n3
> >python  2545 [000] 11064.268083:  raw_syscalls:sys_exit: NR 1 = 4
> >python  2545 [000] 11064.268084: raw_syscalls:sys_enter: NR 1 
> > (1, 12cc330, 4, 7fc237280370, 7fc2373d0700, 2c7b0)
> >python  2545 [000] 11064.268086:  raw_syscalls:sys_exit: NR 1 = 4
> >  # ./perf script -i ./perf.data.2017110101290 | head -n3
> >  failed to open ./perf.data.2017110101290: No such file or directory
> >  # ./perf script -i ./perf.data.2017110101290053 | head -n3
> >python  2545 [000] 11071.564062: raw_syscalls:sys_enter: NR 1 
> > (1, 12cc330, 4, 7fc237280370, 7fc2373d0700, 2c7b0)
> >python  2545 [000] 11071.564064:  raw_syscalls:sys_exit: NR 1 = 4
> >python  2545 [000] 11071.564066: raw_syscalls:sys_enter: NR 1 
> > (1, 12cc330, 4, 7fc237280370, 7fc2373d0700, 2c7b0)
> >  # ./perf script -i ./perf.data.2017110101290 | head -n3
> >  perf.data.2017110101290053  perf.data.2017110101290446  
> > perf.data.2017110101290837
> >  # ./perf script -i ./perf.data.2017110101290446 | head -n3
> >  sshd  1321 [000] 11075.499473:  raw_syscalls:sys_exit: NR 14 = > > 0
> >  sshd  1321 [000] 11075.499474: raw_syscalls:sys_enter: NR 14 
> > (2, 7ffe98899490, 0, 8, 0, 3000)
> >  sshd  1321 [000] 11075.499474:  raw_syscalls:sys_exit: NR 14 = > > 0
> >  # ./perf script -i ./perf.data.2017110101290837 | head -n3
> >python  2545 [000] 11079.280844:  raw_syscalls:sys_exit: NR 1 = 4
> >python  2545 [000] 11079.280847: raw_syscalls:sys_enter: NR 1 
> > (1, 12cc330, 4, 7fc237280370, 7fc2373d0700, 2c7b0)
> >python  2545 [000] 11079.280850:  raw_syscalls:sys_exit: NR 1 = 4
> > 
> > Signed-off-by: Wang Nan 
> > ---
> >  tools/perf/util/evlist.c | 9 +
> >  1 file changed, 5 insertions(+), 4 deletions(-)
> > 
> > diff --git

Re: [PATCH v2 6/8] perf mmap: Fix perf backward recording

2017-12-04 Thread Arnaldo Carvalho de Melo 
Em Mon, Dec 04, 2017 at 02:37:44PM +0900, Namhyung Kim escreveu:
> Hi,
> 
> On Sun, Dec 03, 2017 at 02:00:42AM +, Wang Nan wrote:
> > perf record backward recording doesn't work as we expected: it never
> > overwrite when ring buffer full.
> > 
> > Test:
> > 
> > (Run a busy printing task background like this:
> > 
> >  while True:
> >  print 123
> > 
> > send SIGUSR2 to perf to capture snapshot.)
> > 
> >  # ./perf record --overwrite -e raw_syscalls:sys_enter -e 
> > raw_syscalls:sys_exit --exclude-perf -a --switch-output
> >  [ perf record: dump data: Woken up 1 times ]
> >  [ perf record: Dump perf.data.2017110101520743 ]
> >  [ perf record: dump data: Woken up 1 times ]
> >  [ perf record: Dump perf.data.2017110101521251 ]
> >  [ perf record: dump data: Woken up 1 times ]
> >  [ perf record: Dump perf.data.2017110101521692 ]
> >  ^C[ perf record: Woken up 1 times to write data ]
> >  [ perf record: Dump perf.data.2017110101521936 ]
> >  [ perf record: Captured and wrote 0.826 MB perf.data. ]
> > 
> >  # ./perf script -i ./perf.data.2017110101520743 | head -n3
> >  perf  2717 [000] 12449.310785: raw_syscalls:sys_enter: NR 16 
> > (5, 2400, 0, 59, 100, 0)
> >  perf  2717 [000] 12449.310790: raw_syscalls:sys_enter: NR 7 
> > (4112340, 2, , 3df, 100, 0)
> >python  2545 [000] 12449.310800:  raw_syscalls:sys_exit: NR 1 = 4
> >  # ./perf script -i ./perf.data.2017110101521251 | head -n3
> >  perf  2717 [000] 12449.310785: raw_syscalls:sys_enter: NR 16 
> > (5, 2400, 0, 59, 100, 0)
> >  perf  2717 [000] 12449.310790: raw_syscalls:sys_enter: NR 7 
> > (4112340, 2, , 3df, 100, 0)
> >python  2545 [000] 12449.310800:  raw_syscalls:sys_exit: NR 1 = 4
> >  # ./perf script -i ./perf.data.2017110101521692 | head -n3
> >  perf  2717 [000] 12449.310785: raw_syscalls:sys_enter: NR 16 
> > (5, 2400, 0, 59, 100, 0)
> >  perf  2717 [000] 12449.310790: raw_syscalls:sys_enter: NR 7 
> > (4112340, 2, , 3df, 100, 0)
> >python  2545 [000] 12449.310800:  raw_syscalls:sys_exit: NR 1 = 4
> > 
> > Timestamps are never change, but my background task is a dead loop, can
> > easily overwhelme the ring buffer.
> > 
> > This patch fix it by force unsetting PROT_WRITE for backward ring
> > buffer, so all backward ring buffer become overwrite ring buffer.
> > 
> > Test result:
> > 
> >  # ./perf record --overwrite -e raw_syscalls:sys_enter -e 
> > raw_syscalls:sys_exit --exclude-perf -a --switch-output
> >  [ perf record: dump data: Woken up 1 times ]
> >  [ perf record: Dump perf.data.2017110101285323 ]
> >  [ perf record: dump data: Woken up 1 times ]
> >  [ perf record: Dump perf.data.2017110101290053 ]
> >  [ perf record: dump data: Woken up 1 times ]
> >  [ perf record: Dump perf.data.2017110101290446 ]
> >  ^C[ perf record: Woken up 1 times to write data ]
> >  [ perf record: Dump perf.data.2017110101290837 ]
> >  [ perf record: Captured and wrote 0.826 MB perf.data. ]
> >  # ./perf script -i ./perf.data.2017110101285323 | head -n3
> >python  2545 [000] 11064.268083:  raw_syscalls:sys_exit: NR 1 = 4
> >python  2545 [000] 11064.268084: raw_syscalls:sys_enter: NR 1 
> > (1, 12cc330, 4, 7fc237280370, 7fc2373d0700, 2c7b0)
> >python  2545 [000] 11064.268086:  raw_syscalls:sys_exit: NR 1 = 4
> >  # ./perf script -i ./perf.data.2017110101290 | head -n3
> >  failed to open ./perf.data.2017110101290: No such file or directory
> >  # ./perf script -i ./perf.data.2017110101290053 | head -n3
> >python  2545 [000] 11071.564062: raw_syscalls:sys_enter: NR 1 
> > (1, 12cc330, 4, 7fc237280370, 7fc2373d0700, 2c7b0)
> >python  2545 [000] 11071.564064:  raw_syscalls:sys_exit: NR 1 = 4
> >python  2545 [000] 11071.564066: raw_syscalls:sys_enter: NR 1 
> > (1, 12cc330, 4, 7fc237280370, 7fc2373d0700, 2c7b0)
> >  # ./perf script -i ./perf.data.2017110101290 | head -n3
> >  perf.data.2017110101290053  perf.data.2017110101290446  
> > perf.data.2017110101290837
> >  # ./perf script -i ./perf.data.2017110101290446 | head -n3
> >  sshd  1321 [000] 11075.499473:  raw_syscalls:sys_exit: NR 14 = > > 0
> >  sshd  1321 [000] 11075.499474: raw_syscalls:sys_enter: NR 14 
> > (2, 7ffe98899490, 0, 8, 0, 3000)
> >  sshd  1321 [000] 11075.499474:  raw_syscalls:sys_exit: NR 14 = > > 0
> >  # ./perf script -i ./perf.data.2017110101290837 | head -n3
> >python  2545 [000] 11079.280844:  raw_syscalls:sys_exit: NR 1 = 4
> >python  2545 [000] 11079.280847: raw_syscalls:sys_enter: NR 1 
> > (1, 12cc330, 4, 7fc237280370, 7fc2373d0700, 2c7b0)
> >python  2545 [000] 11079.280850:  raw_syscalls:sys_exit: NR 1 = 4
> > 
> > Signed-off-by: Wang Nan 
> > ---
> >  tools/perf/util/evlist.c | 9 +
> >  1 file changed, 5 insertions(+), 4 deletions(-)
> > 
> > diff --git a/tools/perf/util/evlist.c

Re: [PATCH v2 6/8] perf mmap: Fix perf backward recording

2017-12-03 Thread Namhyung Kim 
Hi,

On Sun, Dec 03, 2017 at 02:00:42AM +, Wang Nan wrote:
> perf record backward recording doesn't work as we expected: it never
> overwrite when ring buffer full.
> 
> Test:
> 
> (Run a busy printing task background like this:
> 
>  while True:
>  print 123
> 
> send SIGUSR2 to perf to capture snapshot.)
> 
>  # ./perf record --overwrite -e raw_syscalls:sys_enter -e 
> raw_syscalls:sys_exit --exclude-perf -a --switch-output
>  [ perf record: dump data: Woken up 1 times ]
>  [ perf record: Dump perf.data.2017110101520743 ]
>  [ perf record: dump data: Woken up 1 times ]
>  [ perf record: Dump perf.data.2017110101521251 ]
>  [ perf record: dump data: Woken up 1 times ]
>  [ perf record: Dump perf.data.2017110101521692 ]
>  ^C[ perf record: Woken up 1 times to write data ]
>  [ perf record: Dump perf.data.2017110101521936 ]
>  [ perf record: Captured and wrote 0.826 MB perf.data. ]
> 
>  # ./perf script -i ./perf.data.2017110101520743 | head -n3
>  perf  2717 [000] 12449.310785: raw_syscalls:sys_enter: NR 16 (5, 
> 2400, 0, 59, 100, 0)
>  perf  2717 [000] 12449.310790: raw_syscalls:sys_enter: NR 7 
> (4112340, 2, , 3df, 100, 0)
>python  2545 [000] 12449.310800:  raw_syscalls:sys_exit: NR 1 = 4
>  # ./perf script -i ./perf.data.2017110101521251 | head -n3
>  perf  2717 [000] 12449.310785: raw_syscalls:sys_enter: NR 16 (5, 
> 2400, 0, 59, 100, 0)
>  perf  2717 [000] 12449.310790: raw_syscalls:sys_enter: NR 7 
> (4112340, 2, , 3df, 100, 0)
>python  2545 [000] 12449.310800:  raw_syscalls:sys_exit: NR 1 = 4
>  # ./perf script -i ./perf.data.2017110101521692 | head -n3
>  perf  2717 [000] 12449.310785: raw_syscalls:sys_enter: NR 16 (5, 
> 2400, 0, 59, 100, 0)
>  perf  2717 [000] 12449.310790: raw_syscalls:sys_enter: NR 7 
> (4112340, 2, , 3df, 100, 0)
>python  2545 [000] 12449.310800:  raw_syscalls:sys_exit: NR 1 = 4
> 
> Timestamps are never change, but my background task is a dead loop, can
> easily overwhelme the ring buffer.
> 
> This patch fix it by force unsetting PROT_WRITE for backward ring
> buffer, so all backward ring buffer become overwrite ring buffer.
> 
> Test result:
> 
>  # ./perf record --overwrite -e raw_syscalls:sys_enter -e 
> raw_syscalls:sys_exit --exclude-perf -a --switch-output
>  [ perf record: dump data: Woken up 1 times ]
>  [ perf record: Dump perf.data.2017110101285323 ]
>  [ perf record: dump data: Woken up 1 times ]
>  [ perf record: Dump perf.data.2017110101290053 ]
>  [ perf record: dump data: Woken up 1 times ]
>  [ perf record: Dump perf.data.2017110101290446 ]
>  ^C[ perf record: Woken up 1 times to write data ]
>  [ perf record: Dump perf.data.2017110101290837 ]
>  [ perf record: Captured and wrote 0.826 MB perf.data. ]
>  # ./perf script -i ./perf.data.2017110101285323 | head -n3
>python  2545 [000] 11064.268083:  raw_syscalls:sys_exit: NR 1 = 4
>python  2545 [000] 11064.268084: raw_syscalls:sys_enter: NR 1 (1, 
> 12cc330, 4, 7fc237280370, 7fc2373d0700, 2c7b0)
>python  2545 [000] 11064.268086:  raw_syscalls:sys_exit: NR 1 = 4
>  # ./perf script -i ./perf.data.2017110101290 | head -n3
>  failed to open ./perf.data.2017110101290: No such file or directory
>  # ./perf script -i ./perf.data.2017110101290053 | head -n3
>python  2545 [000] 11071.564062: raw_syscalls:sys_enter: NR 1 (1, 
> 12cc330, 4, 7fc237280370, 7fc2373d0700, 2c7b0)
>python  2545 [000] 11071.564064:  raw_syscalls:sys_exit: NR 1 = 4
>python  2545 [000] 11071.564066: raw_syscalls:sys_enter: NR 1 (1, 
> 12cc330, 4, 7fc237280370, 7fc2373d0700, 2c7b0)
>  # ./perf script -i ./perf.data.2017110101290 | head -n3
>  perf.data.2017110101290053  perf.data.2017110101290446  
> perf.data.2017110101290837
>  # ./perf script -i ./perf.data.2017110101290446 | head -n3
>  sshd  1321 [000] 11075.499473:  raw_syscalls:sys_exit: NR 14 = 0
>  sshd  1321 [000] 11075.499474: raw_syscalls:sys_enter: NR 14 (2, 
> 7ffe98899490, 0, 8, 0, 3000)
>  sshd  1321 [000] 11075.499474:  raw_syscalls:sys_exit: NR 14 = 0
>  # ./perf script -i ./perf.data.2017110101290837 | head -n3
>python  2545 [000] 11079.280844:  raw_syscalls:sys_exit: NR 1 = 4
>python  2545 [000] 11079.280847: raw_syscalls:sys_enter: NR 1 (1, 
> 12cc330, 4, 7fc237280370, 7fc2373d0700, 2c7b0)
>python  2545 [000] 11079.280850:  raw_syscalls:sys_exit: NR 1 = 4
> 
> Signed-off-by: Wang Nan 
> ---
>  tools/perf/util/evlist.c | 9 +
>  1 file changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
> index 68c1f95..bb70aef 100644
> --- a/tools/perf/util/evlist.c
> +++ b/tools/perf/util/evlist.c
> @@ -799,7 +799,7 @@ perf_evlist__should_poll(struct perf_evlist *evlist 
> __maybe_unused,
>  }
>  
>  static int

Re: [PATCH v2 6/8] perf mmap: Fix perf backward recording

2017-12-03 Thread Namhyung Kim 
Hi,

On Sun, Dec 03, 2017 at 02:00:42AM +, Wang Nan wrote:
> perf record backward recording doesn't work as we expected: it never
> overwrite when ring buffer full.
> 
> Test:
> 
> (Run a busy printing task background like this:
> 
>  while True:
>  print 123
> 
> send SIGUSR2 to perf to capture snapshot.)
> 
>  # ./perf record --overwrite -e raw_syscalls:sys_enter -e 
> raw_syscalls:sys_exit --exclude-perf -a --switch-output
>  [ perf record: dump data: Woken up 1 times ]
>  [ perf record: Dump perf.data.2017110101520743 ]
>  [ perf record: dump data: Woken up 1 times ]
>  [ perf record: Dump perf.data.2017110101521251 ]
>  [ perf record: dump data: Woken up 1 times ]
>  [ perf record: Dump perf.data.2017110101521692 ]
>  ^C[ perf record: Woken up 1 times to write data ]
>  [ perf record: Dump perf.data.2017110101521936 ]
>  [ perf record: Captured and wrote 0.826 MB perf.data. ]
> 
>  # ./perf script -i ./perf.data.2017110101520743 | head -n3
>  perf  2717 [000] 12449.310785: raw_syscalls:sys_enter: NR 16 (5, 
> 2400, 0, 59, 100, 0)
>  perf  2717 [000] 12449.310790: raw_syscalls:sys_enter: NR 7 
> (4112340, 2, , 3df, 100, 0)
>python  2545 [000] 12449.310800:  raw_syscalls:sys_exit: NR 1 = 4
>  # ./perf script -i ./perf.data.2017110101521251 | head -n3
>  perf  2717 [000] 12449.310785: raw_syscalls:sys_enter: NR 16 (5, 
> 2400, 0, 59, 100, 0)
>  perf  2717 [000] 12449.310790: raw_syscalls:sys_enter: NR 7 
> (4112340, 2, , 3df, 100, 0)
>python  2545 [000] 12449.310800:  raw_syscalls:sys_exit: NR 1 = 4
>  # ./perf script -i ./perf.data.2017110101521692 | head -n3
>  perf  2717 [000] 12449.310785: raw_syscalls:sys_enter: NR 16 (5, 
> 2400, 0, 59, 100, 0)
>  perf  2717 [000] 12449.310790: raw_syscalls:sys_enter: NR 7 
> (4112340, 2, , 3df, 100, 0)
>python  2545 [000] 12449.310800:  raw_syscalls:sys_exit: NR 1 = 4
> 
> Timestamps are never change, but my background task is a dead loop, can
> easily overwhelme the ring buffer.
> 
> This patch fix it by force unsetting PROT_WRITE for backward ring
> buffer, so all backward ring buffer become overwrite ring buffer.
> 
> Test result:
> 
>  # ./perf record --overwrite -e raw_syscalls:sys_enter -e 
> raw_syscalls:sys_exit --exclude-perf -a --switch-output
>  [ perf record: dump data: Woken up 1 times ]
>  [ perf record: Dump perf.data.2017110101285323 ]
>  [ perf record: dump data: Woken up 1 times ]
>  [ perf record: Dump perf.data.2017110101290053 ]
>  [ perf record: dump data: Woken up 1 times ]
>  [ perf record: Dump perf.data.2017110101290446 ]
>  ^C[ perf record: Woken up 1 times to write data ]
>  [ perf record: Dump perf.data.2017110101290837 ]
>  [ perf record: Captured and wrote 0.826 MB perf.data. ]
>  # ./perf script -i ./perf.data.2017110101285323 | head -n3
>python  2545 [000] 11064.268083:  raw_syscalls:sys_exit: NR 1 = 4
>python  2545 [000] 11064.268084: raw_syscalls:sys_enter: NR 1 (1, 
> 12cc330, 4, 7fc237280370, 7fc2373d0700, 2c7b0)
>python  2545 [000] 11064.268086:  raw_syscalls:sys_exit: NR 1 = 4
>  # ./perf script -i ./perf.data.2017110101290 | head -n3
>  failed to open ./perf.data.2017110101290: No such file or directory
>  # ./perf script -i ./perf.data.2017110101290053 | head -n3
>python  2545 [000] 11071.564062: raw_syscalls:sys_enter: NR 1 (1, 
> 12cc330, 4, 7fc237280370, 7fc2373d0700, 2c7b0)
>python  2545 [000] 11071.564064:  raw_syscalls:sys_exit: NR 1 = 4
>python  2545 [000] 11071.564066: raw_syscalls:sys_enter: NR 1 (1, 
> 12cc330, 4, 7fc237280370, 7fc2373d0700, 2c7b0)
>  # ./perf script -i ./perf.data.2017110101290 | head -n3
>  perf.data.2017110101290053  perf.data.2017110101290446  
> perf.data.2017110101290837
>  # ./perf script -i ./perf.data.2017110101290446 | head -n3
>  sshd  1321 [000] 11075.499473:  raw_syscalls:sys_exit: NR 14 = 0
>  sshd  1321 [000] 11075.499474: raw_syscalls:sys_enter: NR 14 (2, 
> 7ffe98899490, 0, 8, 0, 3000)
>  sshd  1321 [000] 11075.499474:  raw_syscalls:sys_exit: NR 14 = 0
>  # ./perf script -i ./perf.data.2017110101290837 | head -n3
>python  2545 [000] 11079.280844:  raw_syscalls:sys_exit: NR 1 = 4
>python  2545 [000] 11079.280847: raw_syscalls:sys_enter: NR 1 (1, 
> 12cc330, 4, 7fc237280370, 7fc2373d0700, 2c7b0)
>python  2545 [000] 11079.280850:  raw_syscalls:sys_exit: NR 1 = 4
> 
> Signed-off-by: Wang Nan 
> ---
>  tools/perf/util/evlist.c | 9 +
>  1 file changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
> index 68c1f95..bb70aef 100644
> --- a/tools/perf/util/evlist.c
> +++ b/tools/perf/util/evlist.c
> @@ -799,7 +799,7 @@ perf_evlist__should_poll(struct perf_evlist *evlist 
> __maybe_unused,
>  }
>  
>  static int perf_evlist__mmap_per_evsel(struct

[PATCH v2 6/8] perf mmap: Fix perf backward recording

2017-12-02 Thread Wang Nan 
perf record backward recording doesn't work as we expected: it never
overwrite when ring buffer full.

Test:

(Run a busy printing task background like this:

 while True:
 print 123

send SIGUSR2 to perf to capture snapshot.)

 # ./perf record --overwrite -e raw_syscalls:sys_enter -e raw_syscalls:sys_exit 
--exclude-perf -a --switch-output
 [ perf record: dump data: Woken up 1 times ]
 [ perf record: Dump perf.data.2017110101520743 ]
 [ perf record: dump data: Woken up 1 times ]
 [ perf record: Dump perf.data.2017110101521251 ]
 [ perf record: dump data: Woken up 1 times ]
 [ perf record: Dump perf.data.2017110101521692 ]
 ^C[ perf record: Woken up 1 times to write data ]
 [ perf record: Dump perf.data.2017110101521936 ]
 [ perf record: Captured and wrote 0.826 MB perf.data. ]

 # ./perf script -i ./perf.data.2017110101520743 | head -n3
 perf  2717 [000] 12449.310785: raw_syscalls:sys_enter: NR 16 (5, 
2400, 0, 59, 100, 0)
 perf  2717 [000] 12449.310790: raw_syscalls:sys_enter: NR 7 
(4112340, 2, , 3df, 100, 0)
   python  2545 [000] 12449.310800:  raw_syscalls:sys_exit: NR 1 = 4
 # ./perf script -i ./perf.data.2017110101521251 | head -n3
 perf  2717 [000] 12449.310785: raw_syscalls:sys_enter: NR 16 (5, 
2400, 0, 59, 100, 0)
 perf  2717 [000] 12449.310790: raw_syscalls:sys_enter: NR 7 
(4112340, 2, , 3df, 100, 0)
   python  2545 [000] 12449.310800:  raw_syscalls:sys_exit: NR 1 = 4
 # ./perf script -i ./perf.data.2017110101521692 | head -n3
 perf  2717 [000] 12449.310785: raw_syscalls:sys_enter: NR 16 (5, 
2400, 0, 59, 100, 0)
 perf  2717 [000] 12449.310790: raw_syscalls:sys_enter: NR 7 
(4112340, 2, , 3df, 100, 0)
   python  2545 [000] 12449.310800:  raw_syscalls:sys_exit: NR 1 = 4

Timestamps are never change, but my background task is a dead loop, can
easily overwhelme the ring buffer.

This patch fix it by force unsetting PROT_WRITE for backward ring
buffer, so all backward ring buffer become overwrite ring buffer.

Test result:

 # ./perf record --overwrite -e raw_syscalls:sys_enter -e raw_syscalls:sys_exit 
--exclude-perf -a --switch-output
 [ perf record: dump data: Woken up 1 times ]
 [ perf record: Dump perf.data.2017110101285323 ]
 [ perf record: dump data: Woken up 1 times ]
 [ perf record: Dump perf.data.2017110101290053 ]
 [ perf record: dump data: Woken up 1 times ]
 [ perf record: Dump perf.data.2017110101290446 ]
 ^C[ perf record: Woken up 1 times to write data ]
 [ perf record: Dump perf.data.2017110101290837 ]
 [ perf record: Captured and wrote 0.826 MB perf.data. ]
 # ./perf script -i ./perf.data.2017110101285323 | head -n3
   python  2545 [000] 11064.268083:  raw_syscalls:sys_exit: NR 1 = 4
   python  2545 [000] 11064.268084: raw_syscalls:sys_enter: NR 1 (1, 
12cc330, 4, 7fc237280370, 7fc2373d0700, 2c7b0)
   python  2545 [000] 11064.268086:  raw_syscalls:sys_exit: NR 1 = 4
 # ./perf script -i ./perf.data.2017110101290 | head -n3
 failed to open ./perf.data.2017110101290: No such file or directory
 # ./perf script -i ./perf.data.2017110101290053 | head -n3
   python  2545 [000] 11071.564062: raw_syscalls:sys_enter: NR 1 (1, 
12cc330, 4, 7fc237280370, 7fc2373d0700, 2c7b0)
   python  2545 [000] 11071.564064:  raw_syscalls:sys_exit: NR 1 = 4
   python  2545 [000] 11071.564066: raw_syscalls:sys_enter: NR 1 (1, 
12cc330, 4, 7fc237280370, 7fc2373d0700, 2c7b0)
 # ./perf script -i ./perf.data.2017110101290 | head -n3
 perf.data.2017110101290053  perf.data.2017110101290446  
perf.data.2017110101290837
 # ./perf script -i ./perf.data.2017110101290446 | head -n3
 sshd  1321 [000] 11075.499473:  raw_syscalls:sys_exit: NR 14 = 0
 sshd  1321 [000] 11075.499474: raw_syscalls:sys_enter: NR 14 (2, 
7ffe98899490, 0, 8, 0, 3000)
 sshd  1321 [000] 11075.499474:  raw_syscalls:sys_exit: NR 14 = 0
 # ./perf script -i ./perf.data.2017110101290837 | head -n3
   python  2545 [000] 11079.280844:  raw_syscalls:sys_exit: NR 1 = 4
   python  2545 [000] 11079.280847: raw_syscalls:sys_enter: NR 1 (1, 
12cc330, 4, 7fc237280370, 7fc2373d0700, 2c7b0)
   python  2545 [000] 11079.280850:  raw_syscalls:sys_exit: NR 1 = 4

Signed-off-by: Wang Nan 
---
 tools/perf/util/evlist.c | 9 +
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 68c1f95..bb70aef 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -799,7 +799,7 @@ perf_evlist__should_poll(struct perf_evlist *evlist 
__maybe_unused,
 }
 
 static int perf_evlist__mmap_per_evsel(struct perf_evlist *evlist, int idx,
-  struct mmap_params *mp, int cpu_idx,
+  struct mmap_params mp, int cpu_idx,
   int thread, int *_output, int

[PATCH v2 6/8] perf mmap: Fix perf backward recording

2017-12-02 Thread Wang Nan 
perf record backward recording doesn't work as we expected: it never
overwrite when ring buffer full.

Test:

(Run a busy printing task background like this:

 while True:
 print 123

send SIGUSR2 to perf to capture snapshot.)

 # ./perf record --overwrite -e raw_syscalls:sys_enter -e raw_syscalls:sys_exit 
--exclude-perf -a --switch-output
 [ perf record: dump data: Woken up 1 times ]
 [ perf record: Dump perf.data.2017110101520743 ]
 [ perf record: dump data: Woken up 1 times ]
 [ perf record: Dump perf.data.2017110101521251 ]
 [ perf record: dump data: Woken up 1 times ]
 [ perf record: Dump perf.data.2017110101521692 ]
 ^C[ perf record: Woken up 1 times to write data ]
 [ perf record: Dump perf.data.2017110101521936 ]
 [ perf record: Captured and wrote 0.826 MB perf.data. ]

 # ./perf script -i ./perf.data.2017110101520743 | head -n3
 perf  2717 [000] 12449.310785: raw_syscalls:sys_enter: NR 16 (5, 
2400, 0, 59, 100, 0)
 perf  2717 [000] 12449.310790: raw_syscalls:sys_enter: NR 7 
(4112340, 2, , 3df, 100, 0)
   python  2545 [000] 12449.310800:  raw_syscalls:sys_exit: NR 1 = 4
 # ./perf script -i ./perf.data.2017110101521251 | head -n3
 perf  2717 [000] 12449.310785: raw_syscalls:sys_enter: NR 16 (5, 
2400, 0, 59, 100, 0)
 perf  2717 [000] 12449.310790: raw_syscalls:sys_enter: NR 7 
(4112340, 2, , 3df, 100, 0)
   python  2545 [000] 12449.310800:  raw_syscalls:sys_exit: NR 1 = 4
 # ./perf script -i ./perf.data.2017110101521692 | head -n3
 perf  2717 [000] 12449.310785: raw_syscalls:sys_enter: NR 16 (5, 
2400, 0, 59, 100, 0)
 perf  2717 [000] 12449.310790: raw_syscalls:sys_enter: NR 7 
(4112340, 2, , 3df, 100, 0)
   python  2545 [000] 12449.310800:  raw_syscalls:sys_exit: NR 1 = 4

Timestamps are never change, but my background task is a dead loop, can
easily overwhelme the ring buffer.

This patch fix it by force unsetting PROT_WRITE for backward ring
buffer, so all backward ring buffer become overwrite ring buffer.

Test result:

 # ./perf record --overwrite -e raw_syscalls:sys_enter -e raw_syscalls:sys_exit 
--exclude-perf -a --switch-output
 [ perf record: dump data: Woken up 1 times ]
 [ perf record: Dump perf.data.2017110101285323 ]
 [ perf record: dump data: Woken up 1 times ]
 [ perf record: Dump perf.data.2017110101290053 ]
 [ perf record: dump data: Woken up 1 times ]
 [ perf record: Dump perf.data.2017110101290446 ]
 ^C[ perf record: Woken up 1 times to write data ]
 [ perf record: Dump perf.data.2017110101290837 ]
 [ perf record: Captured and wrote 0.826 MB perf.data. ]
 # ./perf script -i ./perf.data.2017110101285323 | head -n3
   python  2545 [000] 11064.268083:  raw_syscalls:sys_exit: NR 1 = 4
   python  2545 [000] 11064.268084: raw_syscalls:sys_enter: NR 1 (1, 
12cc330, 4, 7fc237280370, 7fc2373d0700, 2c7b0)
   python  2545 [000] 11064.268086:  raw_syscalls:sys_exit: NR 1 = 4
 # ./perf script -i ./perf.data.2017110101290 | head -n3
 failed to open ./perf.data.2017110101290: No such file or directory
 # ./perf script -i ./perf.data.2017110101290053 | head -n3
   python  2545 [000] 11071.564062: raw_syscalls:sys_enter: NR 1 (1, 
12cc330, 4, 7fc237280370, 7fc2373d0700, 2c7b0)
   python  2545 [000] 11071.564064:  raw_syscalls:sys_exit: NR 1 = 4
   python  2545 [000] 11071.564066: raw_syscalls:sys_enter: NR 1 (1, 
12cc330, 4, 7fc237280370, 7fc2373d0700, 2c7b0)
 # ./perf script -i ./perf.data.2017110101290 | head -n3
 perf.data.2017110101290053  perf.data.2017110101290446  
perf.data.2017110101290837
 # ./perf script -i ./perf.data.2017110101290446 | head -n3
 sshd  1321 [000] 11075.499473:  raw_syscalls:sys_exit: NR 14 = 0
 sshd  1321 [000] 11075.499474: raw_syscalls:sys_enter: NR 14 (2, 
7ffe98899490, 0, 8, 0, 3000)
 sshd  1321 [000] 11075.499474:  raw_syscalls:sys_exit: NR 14 = 0
 # ./perf script -i ./perf.data.2017110101290837 | head -n3
   python  2545 [000] 11079.280844:  raw_syscalls:sys_exit: NR 1 = 4
   python  2545 [000] 11079.280847: raw_syscalls:sys_enter: NR 1 (1, 
12cc330, 4, 7fc237280370, 7fc2373d0700, 2c7b0)
   python  2545 [000] 11079.280850:  raw_syscalls:sys_exit: NR 1 = 4

Signed-off-by: Wang Nan 
---
 tools/perf/util/evlist.c | 9 +
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 68c1f95..bb70aef 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -799,7 +799,7 @@ perf_evlist__should_poll(struct perf_evlist *evlist 
__maybe_unused,
 }
 
 static int perf_evlist__mmap_per_evsel(struct perf_evlist *evlist, int idx,
-  struct mmap_params *mp, int cpu_idx,
+  struct mmap_params mp, int cpu_idx,
   int thread, int *_output, int 
*_output_backward)