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Linux内核实时机制x - 实时性之中断响应优化

news 2025/6/25 8:21:33

Linux内核实时机制x - 中断响应优化

日志
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1 非实时内核中断响应测试

0-code/5.15/rt-tests# ./cyclictest -p 90 -m -c 0 -i 1000 -l 1000 -h 100 -t 4
# /dev/cpu_dma_latency set to 0us
policy: fifo: loadavg: 1.04 4.48 6.57 2/1628 385205T: 0 (385170) P:90 I:1000 C:   1000 Min:      3 Act:    3 Avg:    7 Max:     252
T: 1 (385171) P:90 I:1000 C:    999 Min:      3 Act:    5 Avg:    3 Max:      18
T: 2 (385172) P:90 I:1000 C:    999 Min:      3 Act:    4 Avg:    3 Max:      20
T: 3 (385173) P:90 I:1000 C:    999 Min:      3 Act:    4 Avg:    6 Max:     363

2 实时内核中断响应测试

0-code/5.15/rt-tests# trace-cmd start -e all;./cyclictest -p 90 -m -n -c 0 -t 4 -D5m -b 50 --tracemark
# /dev/cpu_dma_latency set to 0us
INFO: debugfs mountpoint: /sys/kernel/debug/tracing/
policy: fifo: loadavg: 6.17 15.98 18.12 2/1152 1691773T: 0 (1691490) P:90 I:1000 C:  31633 Min:      7 Act:   14 Avg:   15 Max:      36
T: 1 (1691491) P:90 I:1500 C:  21049 Min:     10 Act:   15 Avg:   15 Max:      28
T: 2 (1691492) P:90 I:2000 C:  15757 Min:      7 Act:   14 Avg:   15 Max:      40
T: 3 (1691493) P:90 I:2500 C:  12582 Min:      7 Act:   25 Avg:   15 Max:      40
# Thread Ids: 1691490 1691491 1691492 1691493
# Break thread: 1691493
# Break value: 56

2.1 Ftrace抓取日志

0-code/5.15/rt-tests# trace-cmd extract
CPU 0: 1077425 events lost
CPU 1: 1512931 events lost
CPU 2: 764575 events lost
CPU 3: 600860 events lost
CPU 4: 992340 events lost
CPU 5: 1030188 events lost
CPU 6: 1340854 events lost
CPU 7: 781496 events lost
CPU0 data recorded at offset=0x75a0001449984 bytes in size
CPU1 data recorded at offset=0x8bc0001449984 bytes in size
CPU2 data recorded at offset=0xa1e0001449984 bytes in size
CPU3 data recorded at offset=0xb800001449984 bytes in size
CPU4 data recorded at offset=0xce20001449984 bytes in size
CPU5 data recorded at offset=0xe440001449984 bytes in size
CPU6 data recorded at offset=0xfa60001449984 bytes in size
CPU7 data recorded at offset=0x11080001449984 bytes in size0-code/5.15/rt-tests# trace-cmd report -l > log.txt

3 嵌入式板卡-小系统测试结果

~/rt-tests# ./cyclictest -p98 -m -n -D3m -t5 
# /dev/cpu_dma_latency set to 0us 
policy: fifo: loadavg: 2.20 1.73 0.87 1/156 420T: 0 (  414) P:98 I:1000 C: 179997 Min:      4 Act:    5 Avg:    5 Max:       9
T: 1 (  415) P:98 I:1500 C: 119982 Min:      5 Act:    6 Avg:    5 Max:      10
T: 2 (  416) P:98 I:2000 C:  89975 Min:      5 Act:    6 Avg:    5 Max:       8
T: 3 (  417) P:98 I:2500 C:  71970 Min:      5 Act:    6 Avg:    5 Max:       7
T: 4 (  418) P:98 I:3000 C:  59967 Min:      5 Act:    6 Avg:    5 Max:       8

4 实时内核优化参数

cat /proc/osinfo
OS Type:                Desktop
Kernel Version:         5.4.18-87.76 
Source Version:         NA
Build Time:             #  SMP PREEMPT_RT Thu Oct 24 05:30:26 UTC 2024
Architecture:           aarch64
Online CPUs:            4
MemTotal:               8062440 KB
PageSize:               4 KB
Uptime:                 220.16 Sec
Cmdline:                BOOT_IMAGE=/vmlinuz-5.4.18-87.76-rt root=UUID=62db6dc4-b0d2-4beb-9e9b-c2e19006d930 ro quiet splash loglevel=0 console=tty0 resume=UUID=9fb16b7c-2e59-41d3-8de5-146708b4a8ca audit=0 security=none efi=runtime selinux=0 numa_balancing=disable nohlt tsc=reliable rcu_nocb_poll skew_tick=1 isolcpus=2-3 intel_pstate=disable nosoftlockup nohz=on nohz_full=2-3 rcu_nocbs=2-3