From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephane Eranian Date: Wed, 30 Jan 2002 06:54:10 +0000 Subject: Re: [Linux-ia64] What's taking all the system time..? Message-Id: List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org On Wed, Jan 30, 2002 at 05:46:45PM +1100, duraid@fl.net.au wrote: > No flops in this code! > Sometimes, the compiler uses floating point register for integer operations for speed reason. > > Another potential cause could be unaligned accesses. That you can also see > > in the system log. > > 'dmesg' works and sure enough, I get unaligned accesses. But not enough to get > *that* sort of a performance hit, surely? To explain what I'm seeing, each > unaligned access would have to cost 0.05 seconds or so! The kernel DOES NOT generate a printk() for every unaligned accesses you get, it's throttled. Get the address from the syslog and check the code. You may be casting ints into pointers. Linux/ia64 uses the LP64 data model: long and pointers are 64 bits but int are 32 bits only. -- -Stephane