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Stuart Menefy d3ea9fa0a5 sh: Minor optimisations to FPU handling 
A number of small optimisations to FPU handling, in particular:

 - move the task USEDFPU flag from the thread_info flags field (which
   is accessed asynchronously to the thread) to a new status field,
   which is only accessed by the thread itself. This allows locking to
   be removed in most cases, or can be reduced to a preempt_lock().
   This mimics the i386 behaviour.

 - move the modification of regs->sr and thread_info->status flags out
   of save_fpu() to __unlazy_fpu(). This gives the compiler a better
   chance to optimise things, as well as making save_fpu() symmetrical
   with restore_fpu() and init_fpu().

 - implement prepare_to_copy(), so that when creating a thread, we can
   unlazy the FPU prior to copying the thread data structures.

Also make sure that the FPU is disabled while in the kernel, in
particular while booting, and for newly created kernel threads,

In a very artificial benchmark, the execution time for 2500000
context switches was reduced from 50 to 45 seconds.

Signed-off-by: Stuart Menefy <stuart.menefy@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-11-24 17:45:38 +09:00
..
cpu sh: Minor optimisations to FPU handling 2009-11-24 17:45:38 +09:00
vsyscall kbuild: rename ld-option to cc-ldoption 2009-09-20 12:27:42 +02:00
.gitignore sh: Add an arch/sh/kernel/.gitignore 2008-07-29 08:29:32 +09:00
asm-offsets.c sh: Add R-standby sleep mode support 2009-10-30 14:38:45 +09:00
cpufreq.c sh: cpufreq: Include CPU id in info messages. 2009-09-15 09:26:04 +09:00
crash_dump.c kdump: make elfcorehdr_addr independent of CONFIG_PROC_VMCORE 2008-10-20 08:52:39 -07:00
debugtraps.S sh: unwinder: Use a special bug flag for unwinder traps. 2009-08-22 05:28:25 +09:00
disassemble.c sh: Add a simple code dumper for SUPERH32 show_regs(). 2008-12-22 18:43:49 +09:00
dma-nommu.c sh: Revamp PCI DMA coherence Kconfig bits. 2009-10-27 10:35:02 +09:00
dumpstack.c sh: flag the default unwinder as reliable. 2009-08-15 01:09:03 +09:00
dwarf.c Merge branch 'sh/stable-updates' 2009-11-09 10:55:36 +09:00
early_printk.c sh: Fix up early printk build error. 2009-08-04 15:54:33 +09:00
entry-common.S sh: TS_RESTORE_SIGMASK conversion. 2009-10-14 16:05:42 +09:00
ftrace.c sh: ftrace: Make code modification NMI safe. 2009-10-13 16:52:50 +09:00
gpio.c sh: use gpiolib 2009-01-27 14:49:10 +09:00
head_32.S sh: CONFIG_PMB doesn't mean the MMU is in 32bit mode 2009-10-10 21:51:23 +09:00
head_64.S sh: convert to use __HEAD and HEAD_TEXT macros. 2009-04-26 09:20:39 -07:00
idle.c sh: Fix up IRQ re-enabling for the need_resched() case. 2009-10-16 17:55:59 +09:00
init_task.c Use new __init_task_data macro in arch init_task.c files. 2009-09-21 06:27:08 +02:00
io_generic.c sh: Use the generic I/O port base for slowdown. 2009-11-12 16:36:26 +09:00
io_trapped.c sh: Only shout about fixing up unexpected unaligned accesses 2009-08-29 20:31:44 +09:00
io.c sh: Optimise memcpy_to/fromio for SH4 2009-08-24 17:35:07 +09:00
irq_32.c sh: Annotate irq functions with "notrace" 2009-10-27 07:37:10 +09:00
irq_64.c sh: Annotate irq functions with "notrace" 2009-10-27 07:37:10 +09:00
irq.c sh: intc: Handle legacy IRQ reservation in vector map. 2009-11-02 15:43:20 +09:00
kgdb.c sh: Kill off kgdb's magical NMI debouncing. 2009-09-01 17:45:35 +09:00
kprobes.c sh: kprobes: kretprobe_trampoline needs to be global. 2008-09-09 08:13:28 +09:00
localtimer.c sh: Fix up clockevents broadcasting. 2009-08-19 18:00:03 +09:00
machine_kexec.c sh: fix kexec by removing check for old kexec-tools 2009-10-26 19:45:45 +09:00
machvec.c sh: Use the generic I/O port base for slowdown. 2009-11-12 16:36:26 +09:00
Makefile sh: perf events: Preliminary callchain support. 2009-11-05 16:20:09 +09:00
module.c sh: Tidy up the dwarf module helpers. 2009-10-13 13:32:19 +09:00
nmi_debug.c sh: nmi_debug support. 2009-09-01 17:38:32 +09:00
perf_callchain.c sh: perf events: Preliminary callchain support. 2009-11-05 16:20:09 +09:00
perf_event.c sh: perf events: Fix up uninitialized variable warning. 2009-11-05 13:56:50 +09:00
process_32.c sh: Minor optimisations to FPU handling 2009-11-24 17:45:38 +09:00
process_64.c sh: Clean up more superfluous symbol exports. 2009-10-27 11:51:19 +09:00
ptrace_32.c sh: Wire up HAVE_SYSCALL_TRACEPOINTS. 2009-09-16 14:30:34 +09:00
ptrace_64.c sh: Wire up HAVE_SYSCALL_TRACEPOINTS. 2009-09-16 14:30:34 +09:00
relocate_kernel.S sh: add kexec jump support 2009-03-18 18:57:43 +09:00
return_address.c sh: Generalize CALLER_ADDRx support. 2009-10-13 13:10:14 +09:00
setup.c Merge branch 'sh/stable-updates' 2009-10-14 15:53:08 +09:00
sh_bios.c sh: Kill off sh_bios_in_gdb_mode(). 2008-12-22 18:44:44 +09:00
sh_ksyms_32.c sh: Clean up more superfluous symbol exports. 2009-10-27 11:51:19 +09:00
sh_ksyms_64.c sh: Clean up more superfluous symbol exports. 2009-10-27 11:51:19 +09:00
signal_32.c sh: TS_RESTORE_SIGMASK conversion. 2009-10-14 16:05:42 +09:00
signal_64.c sh: TS_RESTORE_SIGMASK conversion. 2009-10-14 16:05:42 +09:00
smp.c Merge branch 'sh/stable-updates' 2009-10-14 15:53:08 +09:00
stacktrace.c sh: stacktrace: Properly terminate the trace entry buffer. 2009-08-15 01:11:37 +09:00
swsusp.c sh: hibernation support 2009-03-10 12:55:40 +09:00
sys_sh32.c headers: utsname.h redux 2009-09-23 18:13:10 -07:00
sys_sh64.c headers: utsname.h redux 2009-09-23 18:13:10 -07:00
sys_sh.c sh: fix sys_cacheflush error checking 2009-08-24 18:59:09 +09:00
syscalls_32.S perf: Do the big rename: Performance Counters -> Performance Events 2009-09-21 14:28:04 +02:00
syscalls_64.S perf: Do the big rename: Performance Counters -> Performance Events 2009-09-21 14:28:04 +02:00
time.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6 2009-09-18 09:43:09 -07:00
topology.c sh: Support SCHED_MC for SH-X3 multi-cores. 2009-10-16 18:00:02 +09:00
traps_32.c sh: Disable SCIF2 on the SH-X3 proto CPU. 2009-10-18 15:13:28 +09:00
traps_64.c sh: Always fixup unaligned userspace accesses on sh64. 2009-05-08 20:32:56 +09:00
traps.c sh64: Fix up the CONFIG_GENERIC_BUG=n build. 2009-11-12 16:39:47 +09:00
unwinder.c sh: unwinder: Use a special bug flag for unwinder traps. 2009-08-22 05:28:25 +09:00
vmlinux.lds.S Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6 2009-09-16 13:48:32 +09:00