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riscv: Reuse measure_cycles() in check_vector_unaligned_access()

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check_vector_unaligned_access() duplicates the logic in measure_cycles().

Reuse measure_cycles() and deduplicate.

Signed-off-by: Nam Cao <namcao@linutronix.de>
Link: https://patch.msgid.link/be4c66fd4120952195fdcd0e62d245c55f0711e2.1770830596.git.namcao@linutronix.de
Signed-off-by: Paul Walmsley <pjw@kernel.org>
This commit is contained in:
Nam Cao 2026-04-03 19:28:47 -06:00 committed by Paul Walmsley
parent 67bdd7b013
commit c03ad15f7c
1 changed files with 8 additions and 46 deletions
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54
arch/riscv/kernel/unaligned_access_speed.c
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@ -16,7 +16,6 @@
#include "copy-unaligned.h"
#define MISALIGNED_ACCESS_JIFFIES_LG2 1
#define MISALIGNED_ACCESS_NS 8000000
#define MISALIGNED_BUFFER_SIZE 0x4000
#define MISALIGNED_BUFFER_ORDER get_order(MISALIGNED_BUFFER_SIZE)
@ -30,9 +29,9 @@ static long unaligned_vector_speed_param = RISCV_HWPROBE_MISALIGNED_VECTOR_UNKNO
static cpumask_t fast_misaligned_access;
#ifdef CONFIG_RISCV_PROBE_UNALIGNED_ACCESS
static u64 measure_cycles(void (*func)(void *dst, const void *src, size_t len),
void *dst, void *src, size_t len)
static u64 __maybe_unused
measure_cycles(void (*func)(void *dst, const void *src, size_t len),
void *dst, void *src, size_t len)
{
u64 start_cycles, end_cycles, cycles = -1ULL;
u64 start_ns;
@ -64,6 +63,7 @@ static u64 measure_cycles(void (*func)(void *dst, const void *src, size_t len),
return cycles;
}
#ifdef CONFIG_RISCV_PROBE_UNALIGNED_ACCESS
static int check_unaligned_access(void *param)
{
int cpu = smp_processor_id();
@ -270,11 +270,9 @@ static int riscv_offline_cpu(unsigned int cpu)
static void check_vector_unaligned_access(struct work_struct *work __always_unused)
{
int cpu = smp_processor_id();
u64 start_cycles, end_cycles;
u64 word_cycles;
u64 byte_cycles;
int ratio;
unsigned long start_jiffies, now;
struct page *page;
void *dst;
void *src;
@ -294,50 +292,14 @@ static void check_vector_unaligned_access(struct work_struct *work __always_unus
/* Unalign src as well, but differently (off by 1 + 2 = 3). */
src = dst + (MISALIGNED_BUFFER_SIZE / 2);
src += 2;
word_cycles = -1ULL;
/* Do a warmup. */
kernel_vector_begin();
__riscv_copy_vec_words_unaligned(dst, src, MISALIGNED_COPY_SIZE);
start_jiffies = jiffies;
while ((now = jiffies) == start_jiffies)
cpu_relax();
/*
* For a fixed amount of time, repeatedly try the function, and take
* the best time in cycles as the measurement.
*/
while (time_before(jiffies, now + (1 << MISALIGNED_ACCESS_JIFFIES_LG2))) {
start_cycles = get_cycles64();
/* Ensure the CSR read can't reorder WRT to the copy. */
mb();
__riscv_copy_vec_words_unaligned(dst, src, MISALIGNED_COPY_SIZE);
/* Ensure the copy ends before the end time is snapped. */
mb();
end_cycles = get_cycles64();
if ((end_cycles - start_cycles) < word_cycles)
word_cycles = end_cycles - start_cycles;
}
byte_cycles = -1ULL;
__riscv_copy_vec_bytes_unaligned(dst, src, MISALIGNED_COPY_SIZE);
start_jiffies = jiffies;
while ((now = jiffies) == start_jiffies)
cpu_relax();
while (time_before(jiffies, now + (1 << MISALIGNED_ACCESS_JIFFIES_LG2))) {
start_cycles = get_cycles64();
/* Ensure the CSR read can't reorder WRT to the copy. */
mb();
__riscv_copy_vec_bytes_unaligned(dst, src, MISALIGNED_COPY_SIZE);
/* Ensure the copy ends before the end time is snapped. */
mb();
end_cycles = get_cycles64();
if ((end_cycles - start_cycles) < byte_cycles)
byte_cycles = end_cycles - start_cycles;
}
word_cycles = measure_cycles(__riscv_copy_vec_words_unaligned,
dst, src, MISALIGNED_COPY_SIZE);
byte_cycles = measure_cycles(__riscv_copy_vec_bytes_unaligned,
dst, src, MISALIGNED_COPY_SIZE);
kernel_vector_end();
/* Don't divide by zero. */