From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bjorn Helgaas Date: Thu, 06 Mar 2003 23:27:32 +0000 Subject: Re: [Linux-ia64] ia64 rwsem using atomic primitive Message-Id: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org > I have converted rw semaphore from current generic spin_lock implementation to use architecture specific atomic operation on ia64. This new scheme speeds up all the semaphore operations in the fast path with atomic instruction and fall back to a heavy function when there are read/write contention. I've also taken some raw measurement how fast it improves. The most significant gain comes from parallel reader lock acquire/release which has around 6.6X speed up with the new version. Here is a patch against 2.4.20. I applied this patch to 2.4. I also picked up David's tweaks to improve the optimization of ia64_fetch_and_add, including the move of that function and related ones to intrinsics.h. Bjorn