1ba7be7d69
Improvements come from eliminating srlz.i, not scheduling AR/CR-reads too early (while there are others still pending), scheduling the backing-store switch as well as possible, splitting the BBB bundle into a MIB/MBB pair. Why is it safe to eliminate the srlz.i? Observe that we used to clear bits ~PSR_PRESERVED_BITS in PSR.L. Since PSR_PRESERVED_BITS==PSR.{UP,MFL,MFH,PK,DT,PP,SP,RT,IC}, we ended up clearing PSR.{BE,AC,I,DFL,DFH,DI,DB,SI,TB}. However, PSR.BE : already is turned off in __kernel_syscall_via_epc() PSR.AC : don't care (kernel normally turns PSR.AC on) PSR.I : already turned off by the time fsys_bubble_down gets invoked PSR.DFL: always 0 (kernel never turns it on) PSR.DFH: don't care --- kernel never touches f32-f127 on its own initiative PSR.DI : always 0 (kernel never turns it on) PSR.SI : always 0 (kernel never turns it on) PSR.DB : don't care --- kernel never enables kernel-level breakpoints PSR.TB : must be 0 already; if it wasn't zero on entry to __kernel_syscall_via_epc, the branch to fsys_bubble_down will trigger a taken branch; the taken-trap-handler then converts the syscall into a break-based system-call. In other words: all the bits we're clearying are either 0 already or are don't cares! Thus, we don't have to write PSR.L at all and we don't have to do a srlz.i either. Good for another ~20 cycle improvement for EPC-based heavy-weight syscalls. Signed-off-by: David Mosberger-Tang <davidm@hpl.hp.com> Signed-off-by: Tony Luck <tony.luck@intel.com> |
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.. | ||
acpi-ext.c | ||
acpi.c | ||
asm-offsets.c | ||
brl_emu.c | ||
cyclone.c | ||
domain.c | ||
efi_stub.S | ||
efi.c | ||
entry.h | ||
entry.S | ||
fsys.S | ||
gate-data.S | ||
gate.lds.S | ||
gate.S | ||
head.S | ||
ia64_ksyms.c | ||
init_task.c | ||
iosapic.c | ||
irq_ia64.c | ||
irq_lsapic.c | ||
irq.c | ||
ivt.S | ||
machvec.c | ||
Makefile | ||
mca_asm.S | ||
mca_drv_asm.S | ||
mca_drv.c | ||
mca_drv.h | ||
mca.c | ||
minstate.h | ||
module.c | ||
pal.S | ||
palinfo.c | ||
patch.c | ||
perfmon_default_smpl.c | ||
perfmon_generic.h | ||
perfmon_itanium.h | ||
perfmon_mckinley.h | ||
perfmon.c | ||
process.c | ||
ptrace.c | ||
sal.c | ||
salinfo.c | ||
semaphore.c | ||
setup.c | ||
sigframe.h | ||
signal.c | ||
smp.c | ||
smpboot.c | ||
sys_ia64.c | ||
time.c | ||
topology.c | ||
traps.c | ||
unaligned.c | ||
unwind_decoder.c | ||
unwind_i.h | ||
unwind.c | ||
vmlinux.lds.S |