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如何判断Solaris上是否支持异步IO作者:eygle
出处:
http://www.eygle.com/blog
日期:December 29, 2004
浏览次数:
377
本文链接:
http://www.eygle.com/archives/2004/12/eciiesolariseie.html
在
Solaris Internals
这本书上，作者提到一段代码用以检测系统是否支持异步I/O.
感觉很有助于理解Solaris系统异步IO的实现以及系统调用。
列在这里和大家分享.
1.源码:
/*
* Quick kaio test. Read 1k bytes from a file using async I/O.
* To compile:
* cc -o aio aio.c -laio
* To run:
* aio file_name
*/
#include
#include
#include
#include
#define BSIZE 1024
main(int argc, char *argv[])
{
aio_result_t res;
char buf[BSIZE];
int fd;
if ((fd=open(argv[1], O_RDONLY)) == -1) {
perror("open");
exit(-1);
}
aioread(fd, buf, BSIZE, 0L, SEEK_SET, &res);
aiowait(0);
if (res.aio_return == BSIZE) {
printf("aio succeeded\n");
close(fd);
exit(0);
}
perror("aio");
}
2.编译:
# cc -o aio aio.c -laio
3.运行:
首先测试裸设备:
# truss -t kaio,lwp_create ./aio /dev/rdsk/c0t0d0s1
kaio(5, 0xFFBEF640, 0x00000000, 0xFF21FB68, 0x00000000, 0xFFBEF648, 0x00000000) = 0
lwp_create(0xFFBEF640, 0, 0xFF21FF5C) = 2
lwp_create() (returning as new lwp ...) = 0
kaio(AIOREAD, 3, 0xFFBEF9C0, 1024, 0, 0xFFBEFDC0) = 0
kaio(AIOWAIT, 0x00000000) = 4290706880
aio succeeded
我们看到，Solaris对于裸设备，最终异步IO调用通过AIOREAD来实现，异步操作成功。
而对于常规文件系统文件的读取:
# truss -t kaio,lwp_create ./aio /a.sh
kaio(5, 0xFFBEF650, 0x00000000, 0xFF21FB68, 0x00000000, 0xFFBEF658, 0x00000000) = 0
lwp_create(0xFFBEF650, 0, 0xFF21FF5C) = 2
lwp_create() (returning as new lwp ...) = 0
kaio(AIOREAD, 3, 0xFFBEF9D0, 1024, 0, 0xFFBEFDD0) Err#48 ENOTSUP
lwp_create(0xFFBEF5F0, 0, 0xFF20DF5C) = 3
lwp_create() (returning as new lwp ...) = 0
lwp_create(0xFFBEF5F0, 0, 0xFF1FBF5C) = 4
lwp_create() (returning as new lwp ...) = 0
lwp_create(0xFFBEF5F0, 0, 0xFF1E9F5C) = 5
lwp_create() (returning as new lwp ...) = 0
lwp_create(0xFFBEF5F0, 0, 0xFF1D7F5C) = 6
lwp_create() (returning as new lwp ...) = 0
lwp_create(0xFFBEF5F0, 0, 0xFF1C5F5C) = 7
lwp_create() (returning as new lwp ...) = 0
lwp_create(0xFFBEF5F0, 0, 0xFF1B3F5C) = 8
lwp_create() (returning as new lwp ...) = 0
lwp_create(0xFFBEF5F0, 0, 0xFF1A1F5C) = 9
lwp_create() (returning as new lwp ...) = 0
lwp_create(0xFFBEF5F0, 0, 0xFF18FF5C) = 10
lwp_create() (returning as new lwp ...) = 0
lwp_create(0xFFBEF5F0, 0, 0xFF17DF5C) = 11
lwp_create() (returning as new lwp ...) = 0
kaio(AIOWAIT, 0x00000000) = 1
kaio(AIONOTIFY, -13008896) = 0
aio succeeded
我们注意到，首先对于AIOREAD系统给出了一个Err#48错误，表明对于文件系统的异步IO不被支持。
最后操作成功，实际上是系统把异步IO调用转化为pread读取。
在完整的truss输出中你可以看到如下一行:
pread64(3, "7F E L F010201\0\0\0\0\0".., 1024, 0) = 1024
而成功的异步IO是通过如下一行来完成读取的:
kaio(AIOREAD, 3, 0xFFBEF9C0, 1024, 0, 0xFFBEFDC0) = 0
下面是完整的truss输出供参考:
# truss /aio a.sh
execve("/aio", 0xFFBEFE4C, 0xFFBEFE58) argc = 2
resolvepath("/usr/lib/ld.so.1", "/usr/lib/ld.so.1", 1023) = 16
open("/var/ld/ld.config", O_RDONLY) Err#2 ENOENT
stat("/usr/lib/libaio.so.1", 0xFFBEF56C) = 0
open("/usr/lib/libaio.so.1", O_RDONLY) = 3
fstat(3, 0xFFBEF56C) = 0
mmap(0x00000000, 8192, PROT_READ|PROT_EXEC, MAP_PRIVATE, 3, 0) = 0xFF3A0000
mmap(0x00000000, 106496, PROT_READ|PROT_EXEC, MAP_PRIVATE, 3, 0) = 0xFF380000
mmap(0xFF398000, 1584, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_FIXED, 3, 32768) = 0xFF398000
munmap(0xFF388000, 65536) = 0
memcntl(0xFF380000, 7184, MC_ADVISE, MADV_WILLNEED, 0, 0) = 0
close(3) = 0
stat("/usr/lib/libc.so.1", 0xFFBEF56C) = 0
open("/usr/lib/libc.so.1", O_RDONLY) = 3
fstat(3, 0xFFBEF56C) = 0
mmap(0xFF3A0000, 8192, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_FIXED, 3, 0) = 0xFF3A0000
mmap(0x00000000, 802816, PROT_READ|PROT_EXEC, MAP_PRIVATE, 3, 0) = 0xFF280000
mmap(0xFF33C000, 24764, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_FIXED, 3, 704512) = 0xFF33C000
munmap(0xFF32C000, 65536) = 0
memcntl(0xFF280000, 113504, MC_ADVISE, MADV_WILLNEED, 0, 0) = 0
close(3) = 0
stat("/usr/lib/libdl.so.1", 0xFFBEF56C) = 0
open("/usr/lib/libdl.so.1", O_RDONLY) = 3
fstat(3, 0xFFBEF56C) = 0
mmap(0xFF3A0000, 8192, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_FIXED, 3, 0) = 0xFF3A0000
close(3) = 0
stat("/usr/platform/SUNW,Ultra-4/lib/libc_psr.so.1", 0xFFBEF37C) = 0
open("/usr/platform/SUNW,Ultra-4/lib/libc_psr.so.1", O_RDONLY) = 3
fstat(3, 0xFFBEF37C) = 0
mmap(0x00000000, 8192, PROT_READ|PROT_EXEC, MAP_PRIVATE, 3, 0) = 0xFF370000
mmap(0x00000000, 8192, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_ANON, -1, 0) = 0xFF360000
mmap(0x00000000, 16384, PROT_READ|PROT_EXEC, MAP_PRIVATE, 3, 0) = 0xFF350000
close(3) = 0
munmap(0xFF370000, 8192) = 0
open("a.sh", O_RDONLY) = 3
sysconfig(_CONFIG_PAGESIZE) = 8192
open("/dev/zero", O_RDWR) = 4
mmap(0x00000000, 1179648, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_NORESERVE, 4, 0) = 0xFF100000
close(4) = 0
mprotect(0xFF100000, 8192, PROT_NONE) = 0
mprotect(0xFF112000, 8192, PROT_NONE) = 0
mprotect(0xFF124000, 8192, PROT_NONE) = 0
mprotect(0xFF136000, 8192, PROT_NONE) = 0
mprotect(0xFF148000, 8192, PROT_NONE) = 0
mprotect(0xFF15A000, 8192, PROT_NONE) = 0
mprotect(0xFF16C000, 8192, PROT_NONE) = 0
mprotect(0xFF17E000, 8192, PROT_NONE) = 0
mprotect(0xFF190000, 8192, PROT_NONE) = 0
mprotect(0xFF1A2000, 8192, PROT_NONE) = 0
mprotect(0xFF1B4000, 8192, PROT_NONE) = 0
mprotect(0xFF1C6000, 8192, PROT_NONE) = 0
mprotect(0xFF1D8000, 8192, PROT_NONE) = 0
mprotect(0xFF1EA000, 8192, PROT_NONE) = 0
mprotect(0xFF1FC000, 8192, PROT_NONE) = 0
mprotect(0xFF20E000, 8192, PROT_NONE) = 0
sigfillset(0xFF3428C8) = 0
kaio(5, 0xFFBEF650, 0x00000000, 0xFF21FB68, 0x00000000, 0xFFBEF658, 0x00000000) = 0
lwp_create(0xFFBEF650, 0, 0xFF21FF5C) = 2
lwp_create() (returning as new lwp ...) = 0
kaio(AIOREAD, 3, 0xFFBEF9D0, 1024, 0, 0xFFBEFDD0) Err#48 ENOTSUP
getpid() = 22727 [22726]
sigaction(SIGPROF, 0xFFBEF798, 0xFF399768) = 0
brk(0x00020B20) = 0
brk(0x0002AB20) = 0
lwp_create(0xFFBEF5F0, 0, 0xFF20DF5C) = 3
lwp_create() (returning as new lwp ...) = 0
lwp_self() = 3
lwp_create(0xFFBEF5F0, 0, 0xFF1FBF5C) = 4
lwp_create() (returning as new lwp ...) = 0
lwp_self() = 4
lwp_create(0xFFBEF5F0, 0, 0xFF1E9F5C) = 5
lwp_create() (returning as new lwp ...) = 0
lwp_self() = 5
lwp_create(0xFFBEF5F0, 0, 0xFF1D7F5C) = 6
lwp_create() (returning as new lwp ...) = 0
lwp_self() = 6
lwp_create(0xFFBEF5F0, 0, 0xFF1C5F5C) = 7
lwp_create() (returning as new lwp ...) = 0
lwp_self() = 7
lwp_create(0xFFBEF5F0, 0, 0xFF1B3F5C) = 8
lwp_create() (returning as new lwp ...) = 0
lwp_self() = 8
lwp_create(0xFFBEF5F0, 0, 0xFF1A1F5C) = 9
lwp_create() (returning as new lwp ...) = 0
lwp_self() = 9
lwp_create(0xFFBEF5F0, 0, 0xFF18FF5C) = 10
lwp_create() (returning as new lwp ...) = 0
lwp_self() = 10
lwp_create(0xFFBEF5F0, 0, 0xFF17DF5C) = 11
lwp_create() (returning as new lwp ...) = 0
lwp_self() = 11
brk(0x0002AB20) = 0
brk(0x0014AB20) = 0
lwp_cond_broadcast(0xFF3997C0) = 0
lwp_cond_signal(0xFF20DFA0) = 0
lwp_cond_wait(0xFF20DFA0, 0xFF20DFB0, 0x00000000) = 0
pread64(3, "7F E L F010201\0\0\0\0\0".., 1024, 0) = 1024
ioctl(1, TCGETA, 0xFFBEEBD4) = 0
aio succeeded
write(1, " a i o s u c c e e d e".., 14) = 14
close(3) = 0
llseek(0, 0, SEEK_CUR) = 14361
_exit(0)
# truss ./aio /dev/rdsk/c0t2d0s5
execve("/aio", 0xFFBEFE3C, 0xFFBEFE48) argc = 2
resolvepath("/usr/lib/ld.so.1", "/usr/lib/ld.so.1", 1023) = 16
open("/var/ld/ld.config", O_RDONLY) Err#2 ENOENT
stat("/usr/lib/libaio.so.1", 0xFFBEF55C) = 0
open("/usr/lib/libaio.so.1", O_RDONLY) = 3
fstat(3, 0xFFBEF55C) = 0
mmap(0x00000000, 8192, PROT_READ|PROT_EXEC, MAP_PRIVATE, 3, 0) = 0xFF3A0000
mmap(0x00000000, 106496, PROT_READ|PROT_EXEC, MAP_PRIVATE, 3, 0) = 0xFF380000
mmap(0xFF398000, 1584, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_FIXED, 3, 32768) = 0xFF398000
munmap(0xFF388000, 65536) = 0
memcntl(0xFF380000, 7184, MC_ADVISE, MADV_WILLNEED, 0, 0) = 0
close(3) = 0
stat("/usr/lib/libc.so.1", 0xFFBEF55C) = 0
open("/usr/lib/libc.so.1", O_RDONLY) = 3
fstat(3, 0xFFBEF55C) = 0
mmap(0xFF3A0000, 8192, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_FIXED, 3, 0) = 0xFF3A0000
mmap(0x00000000, 802816, PROT_READ|PROT_EXEC, MAP_PRIVATE, 3, 0) = 0xFF280000
mmap(0xFF33C000, 24764, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_FIXED, 3, 704512) = 0xFF33C000
munmap(0xFF32C000, 65536) = 0
memcntl(0xFF280000, 113504, MC_ADVISE, MADV_WILLNEED, 0, 0) = 0
close(3) = 0
stat("/usr/lib/libdl.so.1", 0xFFBEF55C) = 0
open("/usr/lib/libdl.so.1", O_RDONLY) = 3
fstat(3, 0xFFBEF55C) = 0
mmap(0xFF3A0000, 8192, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_FIXED, 3, 0) = 0xFF3A0000
close(3) = 0
stat("/usr/platform/SUNW,Ultra-4/lib/libc_psr.so.1", 0xFFBEF36C) = 0
open("/usr/platform/SUNW,Ultra-4/lib/libc_psr.so.1", O_RDONLY) = 3
fstat(3, 0xFFBEF36C) = 0
mmap(0x00000000, 8192, PROT_READ|PROT_EXEC, MAP_PRIVATE, 3, 0) = 0xFF370000
mmap(0x00000000, 8192, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_ANON, -1, 0) = 0xFF360000
mmap(0x00000000, 16384, PROT_READ|PROT_EXEC, MAP_PRIVATE, 3, 0) = 0xFF350000
close(3) = 0
munmap(0xFF370000, 8192) = 0
open("/dev/rdsk/c0t2d0s5", O_RDONLY) = 3
sysconfig(_CONFIG_PAGESIZE) = 8192
open("/dev/zero", O_RDWR) = 4
mmap(0x00000000, 1179648, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_NORESERVE, 4, 0) = 0xFF100000
close(4) = 0
mprotect(0xFF100000, 8192, PROT_NONE) = 0
mprotect(0xFF112000, 8192, PROT_NONE) = 0
mprotect(0xFF124000, 8192, PROT_NONE) = 0
mprotect(0xFF136000, 8192, PROT_NONE) = 0
mprotect(0xFF148000, 8192, PROT_NONE) = 0
mprotect(0xFF15A000, 8192, PROT_NONE) = 0
mprotect(0xFF16C000, 8192, PROT_NONE) = 0
mprotect(0xFF17E000, 8192, PROT_NONE) = 0
mprotect(0xFF190000, 8192, PROT_NONE) = 0
mprotect(0xFF1A2000, 8192, PROT_NONE) = 0
mprotect(0xFF1B4000, 8192, PROT_NONE) = 0
mprotect(0xFF1C6000, 8192, PROT_NONE) = 0
mprotect(0xFF1D8000, 8192, PROT_NONE) = 0
mprotect(0xFF1EA000, 8192, PROT_NONE) = 0
mprotect(0xFF1FC000, 8192, PROT_NONE) = 0
mprotect(0xFF20E000, 8192, PROT_NONE) = 0
sigfillset(0xFF3428C8) = 0
kaio(5, 0xFFBEF640, 0x00000000, 0xFF21FB68, 0x00000000, 0xFFBEF648, 0x00000000) = 0
lwp_create(0xFFBEF640, 0, 0xFF21FF5C) = 2
lwp_create() (returning as new lwp ...) = 0
kaio(AIOREAD, 3, 0xFFBEF9C0, 1024, 0, 0xFFBEFDC0) = 0
kaio(AIOWAIT, 0x00000000) = 4290706880
ioctl(1, TCGETA, 0xFFBEEBC4) = 0
aio succeeded
write(1, " a i o s u c c e e d e".., 14) = 14
close(3) = 0
llseek(0, 0, SEEK_CUR) = 18744
_exit(0)
#
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