Commit f088fc84 authored by Ralf Baechle's avatar Ralf Baechle
Browse files

[MIPS] FPU affinity for MT ASE.


Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent 41c594ab
......@@ -1464,6 +1464,11 @@ config MIPS_VPE_LOADER
endchoice
config MIPS_MT_FPAFF
bool "Dynamic FPU affinity for FP-intensive threads"
depends on MIPS_MT
default y
config MIPS_VPE_LOADER_TOM
bool "Load VPE program into memory hidden from linux"
depends on MIPS_VPE_LOADER
......
......@@ -185,6 +185,17 @@ int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
childregs->cp0_status &= ~(ST0_CU2|ST0_CU1);
clear_tsk_thread_flag(p, TIF_USEDFPU);
#ifdef CONFIG_MIPS_MT_FPAFF
/*
* FPU affinity support is cleaner if we track the
* user-visible CPU affinity from the very beginning.
* The generic cpus_allowed mask will already have
* been copied from the parent before copy_thread
* is invoked.
*/
p->thread.user_cpus_allowed = p->cpus_allowed;
#endif /* CONFIG_MIPS_MT_FPAFF */
if (clone_flags & CLONE_SETTLS)
ti->tp_value = regs->regs[7];
......
......@@ -569,8 +569,19 @@ einval: li v0, -EINVAL
sys sys_tkill 2
sys sys_sendfile64 5
sys sys_futex 6
#ifdef CONFIG_MIPS_MT_FPAFF
/*
* For FPU affinity scheduling on MIPS MT processors, we need to
* intercept sys_sched_xxxaffinity() calls until we get a proper hook
* in kernel/sched.c. Considered only temporary we only support these
* hooks for the 32-bit kernel - there is no MIPS64 MT processor atm.
*/
sys mipsmt_sys_sched_setaffinity 3
sys mipsmt_sys_sched_getaffinity 3
#else
sys sys_sched_setaffinity 3
sys sys_sched_getaffinity 3 /* 4240 */
#endif /* CONFIG_MIPS_MT_FPAFF */
sys sys_io_setup 2
sys sys_io_destroy 1
sys sys_io_getevents 5
......
......@@ -529,7 +529,10 @@ void __init setup_arch(char **cmdline_p)
int __init fpu_disable(char *s)
{
cpu_data[0].options &= ~MIPS_CPU_FPU;
int i;
for (i = 0; i < NR_CPUS; i++)
cpu_data[i].options &= ~MIPS_CPU_FPU;
return 1;
}
......
......@@ -150,6 +150,11 @@ void plat_smp_setup(void)
unsigned long val;
int i, num;
#ifdef CONFIG_MIPS_MT_FPAFF
/* If we have an FPU, enroll ourselves in the FPU-full mask */
if (cpu_has_fpu)
cpu_set(0, mt_fpu_cpumask);
#endif /* CONFIG_MIPS_MT_FPAFF */
if (!cpu_has_mipsmt)
return;
......@@ -312,6 +317,12 @@ void prom_smp_finish(void)
{
write_c0_compare(read_c0_count() + (8* mips_hpt_frequency/HZ));
#ifdef CONFIG_MIPS_MT_FPAFF
/* If we have an FPU, enroll ourselves in the FPU-full mask */
if (cpu_has_fpu)
cpu_set(smp_processor_id(), mt_fpu_cpumask);
#endif /* CONFIG_MIPS_MT_FPAFF */
local_irq_enable();
}
......
......@@ -758,6 +758,36 @@ asmlinkage void do_cpu(struct pt_regs *regs)
&current->thread.fpu.soft);
if (sig)
force_sig(sig, current);
#ifdef CONFIG_MIPS_MT_FPAFF
else {
/*
* MIPS MT processors may have fewer FPU contexts
* than CPU threads. If we've emulated more than
* some threshold number of instructions, force
* migration to a "CPU" that has FP support.
*/
if(mt_fpemul_threshold > 0
&& ((current->thread.emulated_fp++
> mt_fpemul_threshold))) {
/*
* If there's no FPU present, or if the
* application has already restricted
* the allowed set to exclude any CPUs
* with FPUs, we'll skip the procedure.
*/
if (cpus_intersects(current->cpus_allowed,
mt_fpu_cpumask)) {
cpumask_t tmask;
cpus_and(tmask,
current->thread.user_cpus_allowed,
mt_fpu_cpumask);
set_cpus_allowed(current, tmask);
current->thread.mflags |= MF_FPUBOUND;
}
}
}
#endif /* CONFIG_MIPS_MT_FPAFF */
}
return;
......
......@@ -40,7 +40,7 @@
#define cpu_has_sb1_cache (cpu_data[0].options & MIPS_CPU_SB1_CACHE)
#endif
#ifndef cpu_has_fpu
#define cpu_has_fpu (cpu_data[0].options & MIPS_CPU_FPU)
#define cpu_has_fpu (current_cpu_data.options & MIPS_CPU_FPU)
#endif
#ifndef cpu_has_32fpr
#define cpu_has_32fpr (cpu_data[0].options & MIPS_CPU_32FPR)
......
......@@ -21,6 +21,10 @@
#include <asm/processor.h>
#include <asm/current.h>
#ifdef CONFIG_MIPS_MT_FPAFF
#include <asm/mips_mt.h>
#endif
struct sigcontext;
struct sigcontext32;
......
......@@ -134,6 +134,12 @@ struct thread_struct {
/* Saved fpu/fpu emulator stuff. */
union mips_fpu_union fpu;
#ifdef CONFIG_MIPS_MT_FPAFF
/* Emulated instruction count */
unsigned long emulated_fp;
/* Saved per-thread scheduler affinity mask */
cpumask_t user_cpus_allowed;
#endif /* CONFIG_MIPS_MT_FPAFF */
/* Saved state of the DSP ASE, if available. */
struct mips_dsp_state dsp;
......@@ -159,6 +165,12 @@ struct thread_struct {
#define MF_N32 MF_32BIT_ADDR
#define MF_N64 0
#ifdef CONFIG_MIPS_MT_FPAFF
#define FPAFF_INIT 0, INIT_CPUMASK,
#else
#define FPAFF_INIT
#endif /* CONFIG_MIPS_MT_FPAFF */
#define INIT_THREAD { \
/* \
* saved main processor registers \
......@@ -173,6 +185,10 @@ struct thread_struct {
* saved fpu/fpu emulator stuff \
*/ \
INIT_FPU, \
/* \
* fpu affinity state (null if not FPAFF) \
*/ \
FPAFF_INIT \
/* \
* saved dsp/dsp emulator stuff \
*/ \
......
......@@ -155,6 +155,37 @@ extern asmlinkage void *resume(void *last, void *next, void *next_ti);
struct task_struct;
#ifdef CONFIG_MIPS_MT_FPAFF
/*
* Handle the scheduler resume end of FPU affinity management. We do this
* inline to try to keep the overhead down. If we have been forced to run on
* a "CPU" with an FPU because of a previous high level of FP computation,
* but did not actually use the FPU during the most recent time-slice (CU1
* isn't set), we undo the restriction on cpus_allowed.
*
* We're not calling set_cpus_allowed() here, because we have no need to
* force prompt migration - we're already switching the current CPU to a
* different thread.
*/
#define switch_to(prev,next,last) \
do { \
if (cpu_has_fpu && \
(prev->thread.mflags & MF_FPUBOUND) && \
(!(KSTK_STATUS(prev) & ST0_CU1))) { \
prev->thread.mflags &= ~MF_FPUBOUND; \
prev->cpus_allowed = prev->thread.user_cpus_allowed; \
} \
if (cpu_has_dsp) \
__save_dsp(prev); \
next->thread.emulated_fp = 0; \
(last) = resume(prev, next, next->thread_info); \
if (cpu_has_dsp) \
__restore_dsp(current); \
} while(0)
#else
#define switch_to(prev,next,last) \
do { \
if (cpu_has_dsp) \
......@@ -163,6 +194,7 @@ do { \
if (cpu_has_dsp) \
__restore_dsp(current); \
} while(0)
#endif
/*
* On SMP systems, when the scheduler does migration-cost autodetection,
......
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment