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amd64: store per-cpu allocations subtracted by __pcpu

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This eliminates a runtime subtraction from counter_u64_add.

before:
mov    0x4f00ed(%rip),%rax        # 0xffffffff80c01788 <numfullpathfail4>
sub    0x808ff6(%rip),%rax        # 0xffffffff80f1a698 <__pcpu>
addq   $0x1,%gs:(%rax)

after:
mov    0x4f02fd(%rip),%rax        # 0xffffffff80c01788 <numfullpathfail4>
addq   $0x1,%gs:(%rax)

Reviewed by:	jeff
Differential Revision:	https://reviews.freebsd.org/D23570
This commit is contained in:
Mateusz Guzik 2020-02-12 11:12:13 +00:00
parent 3acb6572fc
commit fb886947d9
2 changed files with 8 additions and 2 deletions
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6
sys/amd64/include/counter.h
View File

@ -33,7 +33,7 @@
#include <sys/pcpu.h>
#define EARLY_COUNTER &temp_bsp_pcpu.pc_early_dummy_counter
#define EARLY_COUNTER (void *)__offsetof(struct pcpu, pc_early_dummy_counter)
#define counter_enter() do {} while (0)
#define counter_exit() do {} while (0)
@ -43,6 +43,7 @@ static inline uint64_t
counter_u64_read_one(counter_u64_t c, int cpu)
{
MPASS(c != EARLY_COUNTER);
return (*zpcpu_get_cpu(c, cpu));
}
@ -65,6 +66,7 @@ counter_u64_zero_one_cpu(void *arg)
counter_u64_t c;
c = arg;
MPASS(c != EARLY_COUNTER);
*(zpcpu_get(c)) = 0;
}
@ -86,7 +88,7 @@ counter_u64_add(counter_u64_t c, int64_t inc)
KASSERT(IS_BSP() || c != EARLY_COUNTER, ("EARLY_COUNTER used on AP"));
__asm __volatile("addq\t%1,%%gs:(%0)"
:
: "r" ((char *)c - (char *)&__pcpu[0]), "ri" (inc)
: "r" (c), "ri" (inc)
: "memory", "cc");
}

4
sys/amd64/include/pcpu.h
View File

@ -240,6 +240,10 @@ _Static_assert(sizeof(struct monitorbuf) == 128, "2x cache line");
#define IS_BSP() (PCPU_GET(cpuid) == 0)
#define zpcpu_offset_cpu(cpu) ((uintptr_t)&__pcpu[0] + UMA_PCPU_ALLOC_SIZE * cpu)
#define zpcpu_base_to_offset(base) (void *)((uintptr_t)(base) - (uintptr_t)&__pcpu[0])
#define zpcpu_offset_to_base(base) (void *)((uintptr_t)(base) + (uintptr_t)&__pcpu[0])
#else /* !__GNUCLIKE_ASM || !__GNUCLIKE___TYPEOF */
#error "this file needs to be ported to your compiler"