lkml.org 
[lkml]   [2022]   [Sep]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] perf: Change the layout of perf_sample_data
Date
With recent change, it can set fields only if it's actually used.
Change the data layout so that it can have commonly used fields together
in a cache line boundary. The main user (the perf tools) sets the
IP, TID, TIME, PERIOD always. Also group relevant fields like addr,
phys_addr and data_page_size.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
include/linux/perf_event.h | 35 +++++++++++++++++------------------
1 file changed, 17 insertions(+), 18 deletions(-)

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index e9b151cde491..8c16dae6e6bb 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -1023,25 +1023,13 @@ extern u64 perf_event_read_value(struct perf_event *event,


struct perf_sample_data {
- /*
- * Fields set by perf_sample_data_init(), group so as to
- * minimize the cachelines touched.
- */
u64 sample_flags;
u64 period;
-
+ u64 type;
/*
- * The other fields, optionally {set,used} by
- * perf_{prepare,output}_sample().
+ * Fields set commonly by perf tools, group so as to
+ * minimize the cachelines touched.
*/
- struct perf_branch_stack *br_stack;
- union perf_sample_weight weight;
- union perf_mem_data_src data_src;
- u64 txn;
- u64 addr;
- struct perf_raw_record *raw;
-
- u64 type;
u64 ip;
struct {
u32 pid;
@@ -1049,22 +1037,33 @@ struct perf_sample_data {
} tid_entry;
u64 time;
u64 id;
- u64 stream_id;
struct {
u32 cpu;
u32 reserved;
} cpu_entry;
+
+ /*
+ * The other fields, optionally {set,used} by
+ * perf_{prepare,output}_sample().
+ */
struct perf_callchain_entry *callchain;
- u64 aux_size;
+ struct perf_raw_record *raw;
+ struct perf_branch_stack *br_stack;
+ union perf_sample_weight weight;
+ union perf_mem_data_src data_src;
+ u64 txn;

struct perf_regs regs_user;
struct perf_regs regs_intr;
u64 stack_user_size;

- u64 phys_addr;
+ u64 stream_id;
u64 cgroup;
+ u64 addr;
+ u64 phys_addr;
u64 data_page_size;
u64 code_page_size;
+ u64 aux_size;
} ____cacheline_aligned;

/* default value for data source */
--
2.37.3.998.g577e59143f-goog
\
 
 \ /
  Last update: 2022-09-22 22:56    [W:0.275 / U:0.080 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site