Samuel Thibault <samuel.thiba...@gnu.org> writes:
> Applied, thanks!
Congrats Damien! I don't massively understand this patch, but from what
I have read on the irc logs this improves some performance benchmark by
an order of magnitude. That's pretty stellar!
>
> Damien Zammit, le mer. 16 août 2023 01:44:50 +0000, a ecrit:
>> ---
>> i386/i386/apic.c | 11 +++++------
>> i386/i386/cpu_number.h | 20 +++++++++++++++++++-
>> i386/i386/mp_desc.c | 3 +--
>> x86_64/locore.S | 6 +++---
>> 4 files changed, 28 insertions(+), 12 deletions(-)
>>
>> diff --git a/i386/i386/apic.c b/i386/i386/apic.c
>> index 2bb8e3f1..3a51f506 100644
>> --- a/i386/i386/apic.c
>> +++ b/i386/i386/apic.c
>> @@ -185,7 +185,11 @@ apic_get_num_ioapics(void)
>> int
>> apic_get_current_cpu(void)
>> {
>> - return (lapic->apic_id.r >> 24) & 0xff;
>> + unsigned int eax, ebx, ecx, edx;
>> + eax = 1;
>> + ecx = 0;
>> + cpuid(eax, ebx, ecx, edx);
>> + return (ebx >> 24);
>> }
>>
>>
>> @@ -295,11 +299,6 @@ lapic_enable(void)
>> cpu_intr_save(&flags);
>>
>> apic_id = apic_get_current_cpu();
>> - if (apic_id < 0)
>> - {
>> - printf("apic_get_current_cpu() failed, assuming BSP\n");
>> - apic_id = 0;
>> - }
>>
>> dummy = lapic->dest_format.r;
>> lapic->dest_format.r = 0xffffffff; /* flat model */
>> diff --git a/i386/i386/cpu_number.h b/i386/i386/cpu_number.h
>> index c00896e8..df086370 100644
>> --- a/i386/i386/cpu_number.h
>> +++ b/i386/i386/cpu_number.h
>> @@ -39,12 +39,30 @@
>> #define CX(addr, reg) addr(,reg,8)
>> #endif
>>
>> -#define CPU_NUMBER(reg) \
>> +#define CPU_NUMBER_NO_STACK(reg) \
>> movl %cs:lapic, reg ;\
>> movl %cs:APIC_ID(reg), reg ;\
>> shrl $24, reg ;\
>> movl %cs:CX(cpu_id_lut, reg), reg ;\
>>
>> +/* Never call CPU_NUMBER(%esi) */
>> +#define CPU_NUMBER(reg) \
>> + pushl %esi ;\
>> + pushl %eax ;\
>> + pushl %ebx ;\
>> + pushl %ecx ;\
>> + pushl %edx ;\
>> + movl $1, %eax ;\
>> + cpuid ;\
>> + shrl $24, %ebx ;\
>> + movl %cs:CX(cpu_id_lut, %ebx), %esi ;\
>> + popl %edx ;\
>> + popl %ecx ;\
>> + popl %ebx ;\
>> + popl %eax ;\
>> + movl %esi, reg ;\
>> + popl %esi ;\
>> +
>> #ifndef __ASSEMBLER__
>> #include "kern/cpu_number.h"
>> int cpu_number(void);
>> diff --git a/i386/i386/mp_desc.c b/i386/i386/mp_desc.c
>> index 88fbb50a..f1a1f989 100644
>> --- a/i386/i386/mp_desc.c
>> +++ b/i386/i386/mp_desc.c
>> @@ -275,8 +275,7 @@ cpu_setup(int cpu)
>> void
>> cpu_ap_main()
>> {
>> - unsigned apic_id = (((ApicLocalUnit*)phystokv(lapic_addr))->apic_id.r
>> >> 24) & 0xff;
>> - int cpu = apic_get_cpu_kernel_id(apic_id);
>> + int cpu = cpu_number();
>>
>> do {
>> cpu_pause();
>> diff --git a/x86_64/locore.S b/x86_64/locore.S
>> index a330d56b..c75feb23 100644
>> --- a/x86_64/locore.S
>> +++ b/x86_64/locore.S
>> @@ -1171,7 +1171,7 @@ syscall_entry_2:
>> movq %rdx,R_CS(%rsp) /* fix cs */
>> movq %rbx,R_EFLAGS(%rsp) /* fix eflags */
>>
>> - CPU_NUMBER(%edx)
>> + CPU_NUMBER_NO_STACK(%edx)
>> TIME_TRAP_SENTRY
>>
>> movq CX(EXT(kernel_stack),%rdx),%rbx
>> @@ -1371,7 +1371,7 @@ ENTRY(syscall64)
>> * save only the callee-preserved status according to the C ABI,
>> * plus RIP and EFLAGS for sysret
>> */
>> - CPU_NUMBER(%r11)
>> + CPU_NUMBER_NO_STACK(%r11)
>> movq CX(EXT(active_threads),%r11),%r11 /* point to current thread */
>> movq TH_PCB(%r11),%r11 /* point to pcb */
>> addq $ PCB_ISS,%r11 /* point to saved state */
>> @@ -1405,7 +1405,7 @@ ENTRY(syscall64)
>> mov %r10,%rcx /* fix arg3 location according to C ABI
>> */
>>
>> /* switch to kernel stack, then we can enable interrupts */
>> - CPU_NUMBER(%r11)
>> + CPU_NUMBER_NO_STACK(%r11)
>> movq CX(EXT(kernel_stack),%r11),%rsp
>> sti
>>
>> --
>> 2.40.1
>>
>>
>>
--
Joshua Branson
Sent from the Hurd
