From 4750cf4202c29a895639b89099a7bdbe9ae422b6 Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Tue, 24 Apr 2012 16:32:23 -0400 Subject: ditch the priority inheritance locks; use malloc's version of lock i did some testing trying to switch malloc to use the new internal lock with priority inheritance, and my malloc contention test got 20-100 times slower. if priority inheritance futexes are this slow, it's simply too high a price to pay for avoiding priority inversion. maybe we can consider them somewhere down the road once the kernel folks get their act together on this (and perferably don't link it to glibc's inefficient lock API)... as such, i've switch __lock to use malloc's implementation of lightweight locks, and updated all the users of the code to use an array with a waiter count for their locks. this should give optimal performance in the vast majority of cases, and it's simple. malloc is still using its own internal copy of the lock code because it seems to yield measurably better performance with -O3 when it's inlined (20% or more difference in the contention stress test). --- src/dirent/__dirent.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'src/dirent/__dirent.h') diff --git a/src/dirent/__dirent.h b/src/dirent/__dirent.h index 07b3ee68..38a27b06 100644 --- a/src/dirent/__dirent.h +++ b/src/dirent/__dirent.h @@ -1,9 +1,9 @@ struct __DIR_s { - int lock; int fd; off_t tell; int buf_pos; int buf_end; + int lock[2]; char buf[2048]; }; -- cgit v1.2.1