On Fri, 22 Jul 2005 at 13:27:56 +1000, Andrew Morton wrote:
> Chuck Ebbert <[email protected]> wrote:
> > After:
> >
> > 12534 math_state_restore 130.5625
> > 8354 device_not_available 203.7561
> > -----
> > 20888
> > Next step should be to physically place math_state_restore() after
> > device_not_available(). Would such a patch be accepted? (Yes it
> > would be ugly and require linker script changes.)
>
> Depends on the benefit/ugly ratio ;)
This patch (may not apply cleanly to unpatched -rc3) drops overhead
a few more percent:
11835 math_state_restore 144.3293
8096 device_not_available 197.4634
-----
19931
Most of the exception/interrupt handlers should get the same treatment but
the linker script would grow.
Signed-off-by: Chuck Ebbert <[email protected]>
Index: 2.6.13-rc3a/arch/i386/kernel/entry.S
===================================================================
--- 2.6.13-rc3a.orig/arch/i386/kernel/entry.S 2005-07-16 18:09:48.000000000 -0400
+++ 2.6.13-rc3a/arch/i386/kernel/entry.S 2005-07-22 05:19:22.000000000 -0400
@@ -469,6 +469,7 @@
pushl $do_simd_coprocessor_error
jmp error_code
+ .section ".text.i387_1", "a"
ENTRY(device_not_available)
pushl $-1 # mark this as an int
SAVE_ALL
@@ -484,6 +485,8 @@
addl $4, %esp
jmp ret_from_exception
+ .previous
+
/*
* Debug traps and NMI can happen at the one SYSENTER instruction
* that sets up the real kernel stack. Check here, since we can't
Index: 2.6.13-rc3a/arch/i386/kernel/traps.c
===================================================================
--- 2.6.13-rc3a.orig/arch/i386/kernel/traps.c 2005-07-16 18:05:40.000000000 -0400
+++ 2.6.13-rc3a/arch/i386/kernel/traps.c 2005-07-22 14:02:50.000000000 -0400
@@ -972,7 +972,8 @@
* Must be called with kernel preemption disabled (in this case,
* local interrupts are disabled at the call-site in entry.S).
*/
-asmlinkage void math_state_restore(struct pt_regs regs)
+asmlinkage void __attribute__((__section__(".text.i387_2")))
+math_state_restore(struct pt_regs regs)
{
struct thread_info *thread = current_thread_info();
struct task_struct *tsk = thread->task;
Index: 2.6.13-rc3a/arch/i386/kernel/vmlinux.lds.S
===================================================================
--- 2.6.13-rc3a.orig/arch/i386/kernel/vmlinux.lds.S 2005-07-16 18:05:39.000000000 -0400
+++ 2.6.13-rc3a/arch/i386/kernel/vmlinux.lds.S 2005-07-22 05:20:30.000000000 -0400
@@ -20,6 +20,8 @@
_text = .; /* Text and read-only data */
.text : AT(ADDR(.text) - LOAD_OFFSET) {
*(.text)
+ *(.text.i387_1)
+ *(.text.i387_2)
SCHED_TEXT
LOCK_TEXT
*(.fixup)
__
Chuck
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
| |
 |