On Fri, Sep 13, 2013 at 08:51:33AM +0800, Fengguang Wu wrote:Hi Peter,
FYI, we noticed much increased vmap_area_lock contentions since this
commit:
commit 20bafb3d23d108bc0a896eb8b7c1501f4f649b77
Author: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
Date: Sat Jun 15 10:21:19 2013 -0400
n_tty: Move buffers into n_tty_data
Reduce pointer reloading and improve locality-of-reference;
allocate read_buf and echo_buf within struct n_tty_data.
Here are some comparison between this commit [o] with its parent commit [*].
8cb06c983822103da1cf 20bafb3d23d108bc0a89
------------------------ ------------------------
976.67 +108.3% 2034.67 lkp-a04/micro/netperf/120s-200%-TCP_STREAM
8971.36 +11.4% 9997.05 nhm-white/micro/aim7/exec_test
9948.03 +20.9% 12031.72 TOTAL slabinfo.kmalloc-128.active_objs
8cb06c983822103da1cf 20bafb3d23d108bc0a89
------------------------ ------------------------
976.67 +108.3% 2034.67 lkp-a04/micro/netperf/120s-200%-TCP_STREAM
9127.64 +11.4% 10164.15 nhm-white/micro/aim7/exec_test
10104.31 +20.7% 12198.82 TOTAL slabinfo.kmalloc-128.num_objs