Linux kernel 为什么内核启动太迟了？
我有zynq microzed板，我的日志消息如下…Linux kernel 为什么内核启动太迟了？,linux-kernel,linux-device-driver,embedded-linux,bootloader,u-boot,Linux Kernel,Linux Device Driver,Embedded Linux,Bootloader,U Boot,我有zynq microzed板，我的日志消息如下… [Mon Jun 09 19:28:38.231 2014] SF: Detected S25FL129P_64K/S25FL128S_64K with page size 64 KiB, total 16 MiB [Mon Jun 09 19:28:38.446 2014] SF: 1245184 bytes @ 0x520000 Read: OK [Mon Jun 09 19:28:38.446 2014] ## Loading kern
[Mon Jun 09 19:28:38.231 2014] SF: Detected S25FL129P_64K/S25FL128S_64K with page size 64 KiB, total 16 MiB
[Mon Jun 09 19:28:38.446 2014] SF: 1245184 bytes @ 0x520000 Read: OK
[Mon Jun 09 19:28:38.446 2014] ## Loading kernel from FIT Image at 01000000 ...
[Mon Jun 09 19:28:38.446 2014] Using 'conf@1' configuration
[Mon Jun 09 19:28:38.446 2014] Trying 'kernel@1' kernel subimage
[Mon Jun 09 19:28:38.446 2014] Description: PetaLinux Kernel
[Mon Jun 09 19:28:38.446 2014] Type: Kernel Image
[Mon Jun 09 19:28:38.446 2014] Compression: gzip compressed
[Mon Jun 09 19:28:38.446 2014] Data Start: 0x010000f0
[Mon Jun 09 19:28:38.446 2014] Data Size: 1215908 Bytes = 1.2 MiB
[Mon Jun 09 19:28:38.446 2014] Architecture: ARM
[Mon Jun 09 19:28:38.446 2014] OS: Linux
[Mon Jun 09 19:28:38.446 2014] Load Address: 0x00008000
[Mon Jun 09 19:28:38.446 2014] Entry Point: 0x00008000
[Mon Jun 09 19:28:38.446 2014] Verifying Hash Integrity ... OK
[Mon Jun 09 19:28:38.446 2014] ## Loading fdt from FIT Image at 01000000 ...
[Mon Jun 09 19:28:38.490 2014] Using 'conf@1' configuration
[Mon Jun 09 19:28:38.490 2014] Trying 'fdt@1' fdt subimage
[Mon Jun 09 19:28:38.490 2014] Description: Flattened Device Tree blob
[Mon Jun 09 19:28:38.490 2014] Type: Flat Device Tree
[Mon Jun 09 19:28:38.490 2014] Compression: uncompressed
[Mon Jun 09 19:28:38.490 2014] Data Start: 0x01128f44
[Mon Jun 09 19:28:38.490 2014] Data Size: 9766 Bytes = 9.5 KiB
[Mon Jun 09 19:28:38.490 2014] Architecture: ARM
[Mon Jun 09 19:28:38.490 2014] Hash algo: crc32
[Mon Jun 09 19:28:38.490 2014] Hash value: fad9c7a8
[Mon Jun 09 19:28:38.490 2014] Hash algo: sha1
[Mon Jun 09 19:28:38.490 2014] Hash value: 4ffcd311a61838768c94b2cb0c2e3d5312861fb4
[Mon Jun 09 19:28:38.490 2014] Verifying Hash Integrity ... crc32+ sha1+ OK
[Mon Jun 09 19:28:38.490 2014] Booting using the fdt blob at 0x1128f44
[Mon Jun 09 19:28:38.492 2014] Uncompressing Kernel Image ... OK
[Mon Jun 09 19:28:38.595 2014] Loading Device Tree to 07ffa000, end 07fff625 ... OK
[Mon Jun 09 19:28:38.595 2014]
[Mon Jun 09 19:28:38.595 2014] Starting kernel ...
[Mon Jun 09 19:28:38.595 2014]
[Mon Jun 09 19:28:39.137 2014] Booting Linux on physical CPU 0x0
[Mon Jun 09 19:28:39.137 2014] Linux version 3.8.11 (root@xilinx) (gcc version 4.7.3 (Sourcery CodeBench Lite 2013.05-40) ) #33 SMP PREEMPT Mon Jun 9 19:23:59 IST 2014
[Mon Jun 09 19:28:39.137 2014] CPU: ARMv7 Processor [413fc090] revision 0 (ARMv7), cr=18c53c7d
[Mon Jun 09 19:28:39.137 2014] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
[Mon Jun 09 19:28:39.137 2014] Machine: Xilinx Zynq Platform, model: suheb_24
[Mon Jun 09 19:28:39.137 2014] Memory policy: ECC disabled, Data cache writealloc
[Mon Jun 09 19:28:39.137 2014] PERCPU: Embedded 7 pages/cpu @c0aa3000 s5568 r8192 d14912 u32768
[Mon Jun 09 19:28:39.137 2014] Built 1 zonelists in Zone order, mobility grouping on. Total pages: 260096
[Mon Jun 09 19:28:39.181 2014] Kernel command line: console=ttyPS0,115200
[Mon Jun 09 19:28:39.181 2014] PID hash table entries: 4096 (order: 2, 16384 bytes)
[Mon Jun 09 19:28:39.181 2014] Dentry cache hash table entries: 131072 (order: 7, 524288 bytes)
[Mon Jun 09 19:28:39.181 2014] Inode-cache hash table entries: 65536 (order: 6, 262144 bytes)
[Mon Jun 09 19:28:39.181 2014] __ex_table already sorted, skipping sort
[Mon Jun 09 19:28:39.181 2014] Memory: 1024MB = 1024MB total
[Mon Jun 09 19:28:39.181 2014] Memory: 1036800k/1036800k available, 11776k reserved, 270336K highmem
[Mon Jun 09 19:28:39.181 2014] Virtual kernel memory layout:
[Mon Jun 09 19:28:39.181 2014] vector : 0xffff0000 - 0xffff1000 ( 4 kB)
[Mon Jun 09 19:28:39.181 2014] fixmap : 0xfff00000 - 0xfffe0000 ( 896 kB)
[Mon Jun 09 19:28:39.226 2014] vmalloc : 0xf0000000 - 0xff000000 ( 240 MB)
[Mon Jun 09 19:28:39.226 2014] lowmem : 0xc0000000 - 0xef800000 ( 760 MB)
[Mon Jun 09 19:28:39.226 2014] pkmap : 0xbfe00000 - 0xc0000000 ( 2 MB)
[Mon Jun 09 19:28:39.226 2014] modules : 0xbf000000 - 0xbfe00000 ( 14 MB)
[Mon Jun 09 19:28:39.226 2014] .text : 0xc0008000 - 0xc01b8c4c (1732 kB)
[Mon Jun 09 19:28:39.226 2014] .init : 0xc01b9000 - 0xc02785c0 ( 766 kB)
[Mon Jun 09 19:28:39.226 2014] .data : 0xc027a000 - 0xc0289980 ( 63 kB)
[Mon Jun 09 19:28:39.226 2014] .bss : 0xc0289980 - 0xc0298798 ( 60 kB)
[Mon Jun 09 19:28:39.226 2014] Preemptible hierarchical RCU implementation.
[Mon Jun 09 19:28:39.226 2014] RCU restricting CPUs from NR_CPUS=4 to nr_cpu_ids=2.
[Mon Jun 09 19:28:39.267 2014] NR_IRQS:16 nr_irqs:16 16
[Mon Jun 09 19:28:39.267 2014] xslcr mapped to f0002000
[Mon Jun 09 19:28:39.267 2014] Zynq clock init
[Mon Jun 09 19:28:39.267 2014] sched_clock: 16 bits at 54kHz, resolution 18432ns, wraps every 1207ms
[Mon Jun 09 19:28:39.267 2014] ps7-ttc #0 at f0004000, irq=43
[Mon Jun 09 19:28:38.595 2014] Starting kernel ...
[Mon Jun 09 19:28:38.595 2014]
[Mon Jun 09 19:28:39.137 2014] Booting Linux on physical CPU 0x0
[Mon Jun 09 19:28:38.231 2014] SF: Detected S25FL129P_64K/S25FL128S_64K with page size 64 KiB, total 16 MiB
[Mon Jun 09 19:28:38.446 2014] SF: 1245184 bytes @ 0x520000 Read: OK
[Mon Jun 09 19:28:38.446 2014] ## Loading kernel from FIT Image at 01000000 ...
[Mon Jun 09 19:28:38.446 2014] Using 'conf@1' configuration
[Mon Jun 09 19:28:38.446 2014] Trying 'kernel@1' kernel subimage
[Mon Jun 09 19:28:38.446 2014] Description: PetaLinux Kernel
[Mon Jun 09 19:28:38.446 2014] Type: Kernel Image
[Mon Jun 09 19:28:38.446 2014] Compression: gzip compressed
[Mon Jun 09 19:28:38.446 2014] Data Start: 0x010000f0
[Mon Jun 09 19:28:38.446 2014] Data Size: 1215908 Bytes = 1.2 MiB
[Mon Jun 09 19:28:38.446 2014] Architecture: ARM
[Mon Jun 09 19:28:38.446 2014] OS: Linux
[Mon Jun 09 19:28:38.446 2014] Load Address: 0x00008000
[Mon Jun 09 19:28:38.446 2014] Entry Point: 0x00008000
[Mon Jun 09 19:28:38.446 2014] Verifying Hash Integrity ... OK
[Mon Jun 09 19:28:38.446 2014] ## Loading fdt from FIT Image at 01000000 ...
[Mon Jun 09 19:28:38.490 2014] Using 'conf@1' configuration
[Mon Jun 09 19:28:38.490 2014] Trying 'fdt@1' fdt subimage
[Mon Jun 09 19:28:38.490 2014] Description: Flattened Device Tree blob
[Mon Jun 09 19:28:38.490 2014] Type: Flat Device Tree
[Mon Jun 09 19:28:38.490 2014] Compression: uncompressed
[Mon Jun 09 19:28:38.490 2014] Data Start: 0x01128f44
[Mon Jun 09 19:28:38.490 2014] Data Size: 9766 Bytes = 9.5 KiB
[Mon Jun 09 19:28:38.490 2014] Architecture: ARM
[Mon Jun 09 19:28:38.490 2014] Hash algo: crc32
[Mon Jun 09 19:28:38.490 2014] Hash value: fad9c7a8
[Mon Jun 09 19:28:38.490 2014] Hash algo: sha1
[Mon Jun 09 19:28:38.490 2014] Hash value: 4ffcd311a61838768c94b2cb0c2e3d5312861fb4
[Mon Jun 09 19:28:38.490 2014] Verifying Hash Integrity ... crc32+ sha1+ OK
[Mon Jun 09 19:28:38.490 2014] Booting using the fdt blob at 0x1128f44
[Mon Jun 09 19:28:38.492 2014] Uncompressing Kernel Image ... OK
[Mon Jun 09 19:28:38.595 2014] Loading Device Tree to 07ffa000, end 07fff625 ... OK
[Mon Jun 09 19:28:38.595 2014]
[Mon Jun 09 19:28:38.595 2014] Starting kernel ...
[Mon Jun 09 19:28:38.595 2014]
[Mon Jun 09 19:28:39.137 2014] Booting Linux on physical CPU 0x0
[Mon Jun 09 19:28:39.137 2014] Linux version 3.8.11 (root@xilinx) (gcc version 4.7.3 (Sourcery CodeBench Lite 2013.05-40) ) #33 SMP PREEMPT Mon Jun 9 19:23:59 IST 2014
[Mon Jun 09 19:28:39.137 2014] CPU: ARMv7 Processor [413fc090] revision 0 (ARMv7), cr=18c53c7d
[Mon Jun 09 19:28:39.137 2014] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
[Mon Jun 09 19:28:39.137 2014] Machine: Xilinx Zynq Platform, model: suheb_24
[Mon Jun 09 19:28:39.137 2014] Memory policy: ECC disabled, Data cache writealloc
[Mon Jun 09 19:28:39.137 2014] PERCPU: Embedded 7 pages/cpu @c0aa3000 s5568 r8192 d14912 u32768
[Mon Jun 09 19:28:39.137 2014] Built 1 zonelists in Zone order, mobility grouping on. Total pages: 260096
[Mon Jun 09 19:28:39.181 2014] Kernel command line: console=ttyPS0,115200
[Mon Jun 09 19:28:39.181 2014] PID hash table entries: 4096 (order: 2, 16384 bytes)
[Mon Jun 09 19:28:39.181 2014] Dentry cache hash table entries: 131072 (order: 7, 524288 bytes)
[Mon Jun 09 19:28:39.181 2014] Inode-cache hash table entries: 65536 (order: 6, 262144 bytes)
[Mon Jun 09 19:28:39.181 2014] __ex_table already sorted, skipping sort
[Mon Jun 09 19:28:39.181 2014] Memory: 1024MB = 1024MB total
[Mon Jun 09 19:28:39.181 2014] Memory: 1036800k/1036800k available, 11776k reserved, 270336K highmem
[Mon Jun 09 19:28:39.181 2014] Virtual kernel memory layout:
[Mon Jun 09 19:28:39.181 2014] vector : 0xffff0000 - 0xffff1000 ( 4 kB)
[Mon Jun 09 19:28:39.181 2014] fixmap : 0xfff00000 - 0xfffe0000 ( 896 kB)
[Mon Jun 09 19:28:39.226 2014] vmalloc : 0xf0000000 - 0xff000000 ( 240 MB)
[Mon Jun 09 19:28:39.226 2014] lowmem : 0xc0000000 - 0xef800000 ( 760 MB)
[Mon Jun 09 19:28:39.226 2014] pkmap : 0xbfe00000 - 0xc0000000 ( 2 MB)
[Mon Jun 09 19:28:39.226 2014] modules : 0xbf000000 - 0xbfe00000 ( 14 MB)
[Mon Jun 09 19:28:39.226 2014] .text : 0xc0008000 - 0xc01b8c4c (1732 kB)
[Mon Jun 09 19:28:39.226 2014] .init : 0xc01b9000 - 0xc02785c0 ( 766 kB)
[Mon Jun 09 19:28:39.226 2014] .data : 0xc027a000 - 0xc0289980 ( 63 kB)
[Mon Jun 09 19:28:39.226 2014] .bss : 0xc0289980 - 0xc0298798 ( 60 kB)
[Mon Jun 09 19:28:39.226 2014] Preemptible hierarchical RCU implementation.
[Mon Jun 09 19:28:39.226 2014] RCU restricting CPUs from NR_CPUS=4 to nr_cpu_ids=2.
[Mon Jun 09 19:28:39.267 2014] NR_IRQS:16 nr_irqs:16 16
[Mon Jun 09 19:28:39.267 2014] xslcr mapped to f0002000
[Mon Jun 09 19:28:39.267 2014] Zynq clock init
[Mon Jun 09 19:28:39.267 2014] sched_clock: 16 bits at 54kHz, resolution 18432ns, wraps every 1207ms
[Mon Jun 09 19:28:39.267 2014] ps7-ttc #0 at f0004000, irq=43
[Mon Jun 09 19:28:38.595 2014] Starting kernel ...
[Mon Jun 09 19:28:38.595 2014]
[Mon Jun 09 19:28:39.137 2014] Booting Linux on physical CPU 0x0
[Mon Jun 09 19:28:38.231 2014] SF: Detected S25FL129P_64K/S25FL128S_64K with page size 64 KiB, total 16 MiB
[Mon Jun 09 19:28:38.446 2014] SF: 1245184 bytes @ 0x520000 Read: OK
[Mon Jun 09 19:28:38.446 2014] ## Loading kernel from FIT Image at 01000000 ...
[Mon Jun 09 19:28:38.446 2014] Using 'conf@1' configuration
[Mon Jun 09 19:28:38.446 2014] Trying 'kernel@1' kernel subimage
[Mon Jun 09 19:28:38.446 2014] Description: PetaLinux Kernel
[Mon Jun 09 19:28:38.446 2014] Type: Kernel Image
[Mon Jun 09 19:28:38.446 2014] Compression: gzip compressed
[Mon Jun 09 19:28:38.446 2014] Data Start: 0x010000f0
[Mon Jun 09 19:28:38.446 2014] Data Size: 1215908 Bytes = 1.2 MiB
[Mon Jun 09 19:28:38.446 2014] Architecture: ARM
[Mon Jun 09 19:28:38.446 2014] OS: Linux
[Mon Jun 09 19:28:38.446 2014] Load Address: 0x00008000
[Mon Jun 09 19:28:38.446 2014] Entry Point: 0x00008000
[Mon Jun 09 19:28:38.446 2014] Verifying Hash Integrity ... OK
[Mon Jun 09 19:28:38.446 2014] ## Loading fdt from FIT Image at 01000000 ...
[Mon Jun 09 19:28:38.490 2014] Using 'conf@1' configuration
[Mon Jun 09 19:28:38.490 2014] Trying 'fdt@1' fdt subimage
[Mon Jun 09 19:28:38.490 2014] Description: Flattened Device Tree blob
[Mon Jun 09 19:28:38.490 2014] Type: Flat Device Tree
[Mon Jun 09 19:28:38.490 2014] Compression: uncompressed
[Mon Jun 09 19:28:38.490 2014] Data Start: 0x01128f44
[Mon Jun 09 19:28:38.490 2014] Data Size: 9766 Bytes = 9.5 KiB
[Mon Jun 09 19:28:38.490 2014] Architecture: ARM
[Mon Jun 09 19:28:38.490 2014] Hash algo: crc32
[Mon Jun 09 19:28:38.490 2014] Hash value: fad9c7a8
[Mon Jun 09 19:28:38.490 2014] Hash algo: sha1
[Mon Jun 09 19:28:38.490 2014] Hash value: 4ffcd311a61838768c94b2cb0c2e3d5312861fb4
[Mon Jun 09 19:28:38.490 2014] Verifying Hash Integrity ... crc32+ sha1+ OK
[Mon Jun 09 19:28:38.490 2014] Booting using the fdt blob at 0x1128f44
[Mon Jun 09 19:28:38.492 2014] Uncompressing Kernel Image ... OK
[Mon Jun 09 19:28:38.595 2014] Loading Device Tree to 07ffa000, end 07fff625 ... OK
[Mon Jun 09 19:28:38.595 2014]
[Mon Jun 09 19:28:38.595 2014] Starting kernel ...
[Mon Jun 09 19:28:38.595 2014]
[Mon Jun 09 19:28:39.137 2014] Booting Linux on physical CPU 0x0
[Mon Jun 09 19:28:39.137 2014] Linux version 3.8.11 (root@xilinx) (gcc version 4.7.3 (Sourcery CodeBench Lite 2013.05-40) ) #33 SMP PREEMPT Mon Jun 9 19:23:59 IST 2014
[Mon Jun 09 19:28:39.137 2014] CPU: ARMv7 Processor [413fc090] revision 0 (ARMv7), cr=18c53c7d
[Mon Jun 09 19:28:39.137 2014] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
[Mon Jun 09 19:28:39.137 2014] Machine: Xilinx Zynq Platform, model: suheb_24
[Mon Jun 09 19:28:39.137 2014] Memory policy: ECC disabled, Data cache writealloc
[Mon Jun 09 19:28:39.137 2014] PERCPU: Embedded 7 pages/cpu @c0aa3000 s5568 r8192 d14912 u32768
[Mon Jun 09 19:28:39.137 2014] Built 1 zonelists in Zone order, mobility grouping on. Total pages: 260096
[Mon Jun 09 19:28:39.181 2014] Kernel command line: console=ttyPS0,115200
[Mon Jun 09 19:28:39.181 2014] PID hash table entries: 4096 (order: 2, 16384 bytes)
[Mon Jun 09 19:28:39.181 2014] Dentry cache hash table entries: 131072 (order: 7, 524288 bytes)
[Mon Jun 09 19:28:39.181 2014] Inode-cache hash table entries: 65536 (order: 6, 262144 bytes)
[Mon Jun 09 19:28:39.181 2014] __ex_table already sorted, skipping sort
[Mon Jun 09 19:28:39.181 2014] Memory: 1024MB = 1024MB total
[Mon Jun 09 19:28:39.181 2014] Memory: 1036800k/1036800k available, 11776k reserved, 270336K highmem
[Mon Jun 09 19:28:39.181 2014] Virtual kernel memory layout:
[Mon Jun 09 19:28:39.181 2014] vector : 0xffff0000 - 0xffff1000 ( 4 kB)
[Mon Jun 09 19:28:39.181 2014] fixmap : 0xfff00000 - 0xfffe0000 ( 896 kB)
[Mon Jun 09 19:28:39.226 2014] vmalloc : 0xf0000000 - 0xff000000 ( 240 MB)
[Mon Jun 09 19:28:39.226 2014] lowmem : 0xc0000000 - 0xef800000 ( 760 MB)
[Mon Jun 09 19:28:39.226 2014] pkmap : 0xbfe00000 - 0xc0000000 ( 2 MB)
[Mon Jun 09 19:28:39.226 2014] modules : 0xbf000000 - 0xbfe00000 ( 14 MB)
[Mon Jun 09 19:28:39.226 2014] .text : 0xc0008000 - 0xc01b8c4c (1732 kB)
[Mon Jun 09 19:28:39.226 2014] .init : 0xc01b9000 - 0xc02785c0 ( 766 kB)
[Mon Jun 09 19:28:39.226 2014] .data : 0xc027a000 - 0xc0289980 ( 63 kB)
[Mon Jun 09 19:28:39.226 2014] .bss : 0xc0289980 - 0xc0298798 ( 60 kB)
[Mon Jun 09 19:28:39.226 2014] Preemptible hierarchical RCU implementation.
[Mon Jun 09 19:28:39.226 2014] RCU restricting CPUs from NR_CPUS=4 to nr_cpu_ids=2.
[Mon Jun 09 19:28:39.267 2014] NR_IRQS:16 nr_irqs:16 16
[Mon Jun 09 19:28:39.267 2014] xslcr mapped to f0002000
[Mon Jun 09 19:28:39.267 2014] Zynq clock init
[Mon Jun 09 19:28:39.267 2014] sched_clock: 16 bits at 54kHz, resolution 18432ns, wraps every 1207ms
[Mon Jun 09 19:28:39.267 2014] ps7-ttc #0 at f0004000, irq=43
[Mon Jun 09 19:28:38.595 2014] Starting kernel ...
[Mon Jun 09 19:28:38.595 2014]
[Mon Jun 09 19:28:39.137 2014] Booting Linux on physical CPU 0x0
您能告诉我如何做到这一点吗？您计算运行时间的方法使用了有缺陷的数据。
您所认为的0.5秒“延迟”实际上是U-Boot在实时中输出“启动内核…”，而内核缓冲区和延迟输出其“启动Linux…”，直到系统和控制台初始化。那是把苹果和桔子做比较。
至少你必须让内核实时输出（就像U-Boot一样）。那么时间戳将更好地指示实际经过的时间 当内核执行早期初始化时，中断被禁用，任何到控制台的输出（包括“启动Linux…”消息）都被保存在缓冲区中，直到在中的第572行执行console_init（）。请注意，突出的“在…上引导Linux”文本是例程smp_setup_processor_id（）第478行中启动内核（）过程开头的“输出”。在内核启动时出现“启动Linux on…”文本之前，您注意到的大多数“延迟”都是由控制台输出的缓冲引起的 通过启用内核调试功能early printk
需要两个步骤：
内核黑客攻击
内核底层调试函数
早期印刷
Linux版本3.10…
CPU:ARMv7处理器[410fc051]版本1（ARMv7），cr=10c53c7d
CPU:PIPT/VIPT非冲突数据缓存、VIPT别名指令缓存
机器：Atmel SAMA5（设备树），型号：Atmel SAMA5D36-EK
启动控制台[earlycon0]已启用
内存策略：禁用ECC，数据缓存写回
…
内核命令行：console=ttys0115200earlyprintkrootfstype=ubifs
嗯，您可以重置时钟，或者从内核中删除所有代码…请从将内核映像加载到内存的角度显示更多早期引导日志。使用哪种内核映像（例如映像、zImage或uImage）？如何在0.10秒内“解压缩内核映像”？使用哪种压缩方式？这个CPU有多强大？添加initcall\u debug可能会带来额外的information@sawdust，请检查我的更新日志，我正在使用image.ub作为内核映像。