that's one often-forgotten BKL site: about 1000 ioctls are still running
under the BKL. The TTY one is hurting the most. To make sure it's only
that BKL acquire/release that hurts, could you try the hack patch below,
does it make any difference to performance?
but even if taking the BKL does hurt, it's quite unexpected to cause a
40% drop. Perhaps AIM7 has tons of threads that exit at once and all try
to release their controlling terminal or something like that?
Ingo
------------------------>
Subject: DANGEROUS tty hack: no BKL
From: Ingo Molnar <mingo@elte.hu>
Date: Wed May 07 08:21:22 CEST 2008
NOT-Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
drivers/char/tty_io.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
Index: linux/drivers/char/tty_io.c
===================================================================
--- linux.orig/drivers/char/tty_io.c
+++ linux/drivers/char/tty_io.c
@@ -2844,9 +2844,10 @@ out:
static int tty_release(struct inode *inode, struct file *filp)
{
- lock_kernel();
+ /* DANGEROUS - can crash your kernel! */
+// lock_kernel();
release_dev(filp);
- unlock_kernel();
+// unlock_kernel();
return 0;
}
--
