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// SPDX-License-Identifier: GPL-2.0-only
// Copyright (C) 2021 ARM Limited.
// Original author: Mark Brown <broonie@kernel.org>
//
// Trivial syscall overhead benchmark.
//
// This is implemented in asm to ensure that we don't have any issues with
// system libraries using instructions that disrupt the test.
#include <asm/unistd.h>
#include "assembler.h"
.arch_extension sve
.macro test_loop per_loop
mov x10, x20
mov x8, #__NR_getpid
mrs x11, CNTVCT_EL0
1:
\per_loop
svc #0
sub x10, x10, #1
cbnz x10, 1b
mrs x12, CNTVCT_EL0
sub x0, x12, x11
bl putdec
puts "\n"
.endm
// Main program entry point
.globl _start
function _start
_start:
puts "Iterations per test: "
mov x20, #10000
lsl x20, x20, #8
mov x0, x20
bl putdec
puts "\n"
// Test having never used SVE
puts "No SVE: "
test_loop
// Check for SVE support - should use hwcap but that's hard in asm
mrs x0, ID_AA64PFR0_EL1
ubfx x0, x0, #32, #4
cbnz x0, 1f
puts "System does not support SVE\n"
b out
1:
// Execute a SVE instruction
puts "SVE VL: "
rdvl x0, #8
bl putdec
puts "\n"
puts "SVE used once: "
test_loop
// Use SVE per syscall
puts "SVE used per syscall: "
test_loop "rdvl x0, #8"
// And we're done
out:
mov x0, #0
mov x8, #__NR_exit
svc #0
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