龙芯 Linux 内核 VDSO 现状测试

http://ask.loongnix.org/?/article/418

 

好久之前记得龙芯上 VDSO 支持很有问题，前一阵终于获得少量空闲时间，又测了一下，发现还是不行，跑这么一个脚本发现大量 clock_gettime 系统调用。（amd64 上除了用于实现 sleep 的 select 之外没有任何 gettimeofday 或者 clock_gettime 的调用。）

#!/usr/bin/env python3

import time

for i in range(100):
    time.sleep(0.01)
    _ = time.time()

翻 glibc 源码时候 git log 看到一个叫 vdsotest 的工具，于是弄下来跑了一遍。
 
测试环境：

• 龙芯 3A3000 开发板
• Gentoo MIPS/n64 multilib 安装
• Linux 4.19.14 + 几乎所有 loongson-community 补丁 + 自制补丁 https://github.com/xen0n/linux/commit/b5dd70d483fcc5a7c9176b5d1d5aba62d202c4d7
• binutils 2.31.1 + 龙芯补丁
• gcc 8.2.0 + 龙芯补丁
• glibc 2.28 + 龙芯补丁
• https://github.com/nlynch-mentor/vdsotest

  

clock-gettime-monotonic: syscall: 409 nsec/callclock-gettime-monotonic:    libc: 476 nsec/callclock-gettime-monotonic:    vdso: 462 nsec/callNote: vDSO version of clock_getres not foundclock-getres-monotonic: syscall: 323 nsec/callclock-getres-monotonic:    libc: 346 nsec/callclock-getres-monotonic:    vdso: not testedNote: vDSO version of clock_getres not foundNote: vDSO version of clock_getres not foundclock-gettime-monotonic-coarse: syscall: 374 nsec/callclock-gettime-monotonic-coarse:    libc: 115 nsec/callclock-gettime-monotonic-coarse:    vdso: 98 nsec/callpassing UINTPTR_MAX to clock_gettime (VDSO): terminated by unexpected signal 10clock-gettime-monotonic-coarse/abi: 1 failures/inconsistencies encounteredNote: vDSO version of clock_getres not foundclock-getres-monotonic-coarse: syscall: 357 nsec/callclock-getres-monotonic-coarse:    libc: 379 nsec/callclock-getres-monotonic-coarse:    vdso: not testedNote: vDSO version of clock_getres not foundNote: vDSO version of clock_getres not foundclock-gettime-monotonic-raw: syscall: 406 nsec/callclock-gettime-monotonic-raw:    libc: 455 nsec/callclock-gettime-monotonic-raw:    vdso: 425 nsec/callNote: vDSO version of clock_getres not foundclock-getres-monotonic-raw: syscall: 323 nsec/callclock-getres-monotonic-raw:    libc: 346 nsec/callclock-getres-monotonic-raw:    vdso: not testedNote: vDSO version of clock_getres not foundNote: vDSO version of clock_getres not foundclock-gettime-tai: syscall: 422 nsec/callclock-gettime-tai:    libc: 472 nsec/callclock-gettime-tai:    vdso: 449 nsec/callNote: vDSO version of clock_getres not foundclock-getres-tai: syscall: 323 nsec/callclock-getres-tai:    libc: 345 nsec/callclock-getres-tai:    vdso: not testedNote: vDSO version of clock_getres not foundNote: vDSO version of clock_getres not foundclock-gettime-boottime: syscall: 421 nsec/callclock-gettime-boottime:    libc: 471 nsec/callclock-gettime-boottime:    vdso: 450 nsec/callNote: vDSO version of clock_getres not foundclock-getres-boottime: syscall: 324 nsec/callclock-getres-boottime:    libc: 346 nsec/callclock-getres-boottime:    vdso: not testedNote: vDSO version of clock_getres not foundNote: vDSO version of clock_getres not foundclock-gettime-realtime: syscall: 405 nsec/callclock-gettime-realtime:    libc: 474 nsec/callclock-gettime-realtime:    vdso: 457 nsec/callNote: vDSO version of clock_getres not foundclock-getres-realtime: syscall: 323 nsec/callclock-getres-realtime:    libc: 348 nsec/callclock-ge