lkml.org 
[lkml]   [2009]   [Dec]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [PATCH 1/3] perf: Fix timechart header handling
Date
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 */
};


Thanks.
--
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>


\
 
 \ /
  Last update: 2009-12-06 13:13    [W:0.064 / U:0.844 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site