From: Yuqi Jin <[email protected]>
In the syscall process, @f_count and @f_mod are frequently used, if
we put them together with each other and they will share the same
cacheline. It is useful for the performance.
syscall of unixbench is tested on Intel 8180.
before this patch
80 CPUs in system; running 80 parallel copies of tests
System Call Overhead 3789860.2 lps (10.0 s, 1 samples)
System Benchmarks Partial Index BASELINE RESULT INDEX
System Call Overhead 15000.0 3789860.2 2526.6
========
System Benchmarks Index Score (Partial Only) 2526.6
after this patch
80 CPUs in system; running 80 parallel copies of tests
System Call Overhead 3951328.1 lps (10.0 s, 1 samples)
System Benchmarks Partial Index BASELINE RESULT INDEX
System Call Overhead 15000.0 3951328.1 2634.2
========
System Benchmarks Index Score (Partial Only) 2634.2
Cc: Alexander Viro <[email protected]>
Signed-off-by: Yuqi Jin <[email protected]>
Signed-off-by: Shaokun Zhang <[email protected]>
---
Hi,
Sorry for the noise that I resent the patch since v1[1], while
Intel's robot gives the 19.2% improvement[2].
[1]https://www.spinics.net/lists/linux-fsdevel/msg192888.html
[2]https://www.spinics.net/lists/linux-fsdevel/msg193521.html
include/linux/fs.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index c3c88fdb9b2a..23baa7c8301b 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -922,7 +922,6 @@ struct file {
struct llist_node fu_llist;
struct rcu_head fu_rcuhead;
} f_u;
- struct path f_path;
struct inode *f_inode; /* cached value */
const struct file_operations *f_op;
@@ -931,13 +930,14 @@ struct file {
* Must not be taken from IRQ context.
*/
spinlock_t f_lock;
- enum rw_hint f_write_hint;
atomic_long_t f_count;
unsigned int f_flags;
fmode_t f_mode;
struct mutex f_pos_lock;
loff_t f_pos;
struct fown_struct f_owner;
+ enum rw_hint f_write_hint;
+ struct path f_path;
const struct cred *f_cred;
struct file_ra_state f_ra;
--
2.7.4