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SubjectRe: [PATCH 1/3] perf: Fix timechart header handling

* OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> wrote:

> Ingo Molnar <mingo@elte.hu> writes:
>
> > * OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> wrote:
> >
> >> Hi,
> >>
> >> Update "struct trace_entry" to match with current one. And remove
> >> "size" field from it.
> >>
> >> If it has "size", it become cause of alignment mismatch of structure
> >> with kernel.
> >>
> >> Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
> >> ---
> >>
> >> tools/perf/builtin-timechart.c | 12 ++++++++----
> >> 1 file changed, 8 insertions(+), 4 deletions(-)
> >
> > Just curious, have you tested timechart functionality after having done
> > this change - does it still work fine for you?
>
> Yes. Rather, it doesn't work without this. (Without patch, it provide
> svg output, but it doesn't provide correct sched state. And this issue
> is only 64bit arch.)
>
> E.g. The following has difference (perf timechart doesn't has hole).
>
> In kernel,
>
> struct ftrace_raw_sched_switch {
> struct trace_entry ent; /* 0 12 */
> char prev_comm[16]; /* 12 16 */
> pid_t prev_pid; /* 28 4 */
> int prev_prio; /* 32 4 */
>
> /* XXX 4 bytes hole, try to pack */
>
> long int prev_state; /* 40 8 */
> char next_comm[16]; /* 48 16 */
> /* --- cacheline 1 boundary (64 bytes) --- */
> pid_t next_pid; /* 64 4 */
> int next_prio; /* 68 4 */
> char __data[0]; /* 72 0 */
>
> /* size: 72, cachelines: 2, members: 9 */
> /* sum members: 68, holes: 1, sum holes: 4 */
> /* last cacheline: 8 bytes */
> };
>
> In perl timechart, [Note, struct trace_entry is including "u32 size"]
>
> struct sched_switch {
> struct trace_entry te; /* 0 16 */
> char prev_comm[16]; /* 16 16 */
> int prev_pid; /* 32 4 */
> int prev_prio; /* 36 4 */
> long int prev_state; /* 40 8 */
> char next_comm[16]; /* 48 16 */
> /* --- cacheline 1 boundary (64 bytes) --- */
> int next_pid; /* 64 4 */
> int next_prio; /* 68 4 */
>
> /* size: 72, cachelines: 2, members: 8 */
> /* last cacheline: 8 bytes */
> };
>

ok - thanks for the confirmation!

Ingo


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