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 [*].
489739.50 +978.5% 5281916.05 lkp-ne04/micro/aim7/shell_rtns_1[...]
1601675.63 +906.7% 16123642.52 lkp-snb01/micro/aim7/exec_test
822461.02 +1585.0% 13858430.62 nhm-white/micro/aim7/exec_test[...]
9858.11 +2715.9% 277595.41 nhm-white/micro/aim7/fork_test
300.14 +2621.5% 8168.53 nhm-white/micro/aim7/misc_rtns_1
345479.21 +1624.5% 5957828.25 nhm-white/micro/aim7/shell_rtns_1
lock_stat.vmap_area_lock.contentions.get_vmalloc_info
8cb06c983822103da1cf 20bafb3d23d108bc0a89
------------------------ ------------------------
4952.40 +447.0% 27090.40 lkp-ne04/micro/aim7/shell_rtns_1
28410.80 +556.2% 186423.00 lkp-snb01/micro/aim7/exec_test
8142.00 +615.4% 58247.33 nhm-white/micro/aim7/exec_test
1386.00 +762.6% 11955.20 nhm-white/micro/aim7/shell_rtns_1
42891.20 +561.5% 283715.93 TOTAL lock_stat.vmap_area_lock.contentions.get_vmalloc_info