0001 // SPDX-License-Identifier: GPL-2.0-only
0002 // Copyright (C) 2021 ARM Limited.
0003 // Original author: Mark Brown <broonie@kernel.org>
0004 //
0005 // Trivial syscall overhead benchmark.
0006 //
0007 // This is implemented in asm to ensure that we don't have any issues with
0008 // system libraries using instructions that disrupt the test.
0009
0010 #include <asm/unistd.h>
0011 #include "assembler.h"
0012
0013 .arch_extension sve
0014
0015 .macro test_loop per_loop
0016 mov x10, x20
0017 mov x8, #__NR_getpid
0018 mrs x11, CNTVCT_EL0
0019 1:
0020 \per_loop
0021 svc #0
0022 sub x10, x10, #1
0023 cbnz x10, 1b
0024
0025 mrs x12, CNTVCT_EL0
0026 sub x0, x12, x11
0027 bl putdec
0028 puts "\n"
0029 .endm
0030
0031 // Main program entry point
0032 .globl _start
0033 function _start
0034 _start:
0035 puts "Iterations per test: "
0036 mov x20, #10000
0037 lsl x20, x20, #8
0038 mov x0, x20
0039 bl putdec
0040 puts "\n"
0041
0042 // Test having never used SVE
0043 puts "No SVE: "
0044 test_loop
0045
0046 // Check for SVE support - should use hwcap but that's hard in asm
0047 mrs x0, ID_AA64PFR0_EL1
0048 ubfx x0, x0, #32, #4
0049 cbnz x0, 1f
0050 puts "System does not support SVE\n"
0051 b out
0052 1:
0053
0054 // Execute a SVE instruction
0055 puts "SVE VL: "
0056 rdvl x0, #8
0057 bl putdec
0058 puts "\n"
0059
0060 puts "SVE used once: "
0061 test_loop
0062
0063 // Use SVE per syscall
0064 puts "SVE used per syscall: "
0065 test_loop "rdvl x0, #8"
0066
0067 // And we're done
0068 out:
0069 mov x0, #0
0070 mov x8, #__NR_exit
0071 svc #0
