Commit c03ad15f authored by Nam Cao's avatar Nam Cao Committed by Paul Walmsley
Browse files

riscv: Reuse measure_cycles() in check_vector_unaligned_access() 



check_vector_unaligned_access() duplicates the logic in measure_cycles().

Reuse measure_cycles() and deduplicate.

Signed-off-by: default avatarNam Cao <namcao@linutronix.de>
Link: https://patch.msgid.link/be4c66fd4120952195fdcd0e62d245c55f0711e2.1770830596.git.namcao@linutronix.de


Signed-off-by: default avatarPaul Walmsley <pjw@kernel.org>
parent 67bdd7b0

arch/riscv/kernel/unaligned_access_speed.c

+8 −46
Original line number Diff line number Diff line
@@ -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)
@@ -30,8 +29,8 @@ 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),

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;
@@ -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. */