カーネルの起動が遅すぎるのはなぜですか
ARM CortexA9ベースのボードからのログメッセージ。Linuxを実行しています。
[Sat Apr 12 19:33:50.207 2014]
[Sat Apr 12 19:33:50.207 2014]
[Sat Apr 12 19:33:50.207 2014] U-Boot 2013.07 (Apr 09 2014 - 12:31:52)
[Sat Apr 12 19:33:50.207 2014]
[Sat Apr 12 19:33:50.207 2014] Memory: ECC disabled
[Sat Apr 12 19:33:50.207 2014] DRAM: 1 GiB
[Sat Apr 12 19:33:50.224 2014] MMC: zynq_sdhci: 0
[Sat Apr 12 19:33:50.224 2014] SF: Detected N25Q128A with page size 64 KiB, total 16 MiB
[Sat Apr 12 19:33:50.245 2014] In: serial
[Sat Apr 12 19:33:50.245 2014] Out: serial
[Sat Apr 12 19:33:50.245 2014] Err: serial
[Sat Apr 12 19:33:50.245 2014]
[Sat Apr 12 19:33:50.245 2014] boot Petalinux
[Sat Apr 12 19:33:50.303 2014] Device: zynq_sdhci
[Sat Apr 12 19:33:50.303 2014] Manufacturer ID: 2
[Sat Apr 12 19:33:50.303 2014] OEM: 544d
[Sat Apr 12 19:33:50.303 2014] Name: SA04G
[Sat Apr 12 19:33:50.303 2014] Tran Speed: 50000000
[Sat Apr 12 19:33:50.303 2014] Rd Block Len: 512
[Sat Apr 12 19:33:50.303 2014] SD version 3.0
[Sat Apr 12 19:33:50.303 2014] High Capacity: Yes
[Sat Apr 12 19:33:50.303 2014] Capacity: 3.7 GiB
[Sat Apr 12 19:33:50.303 2014] Bus Width: 4-bit
[Sat Apr 12 19:33:50.303 2014] reading image.ub
[Sat Apr 12 19:33:50.520 2014] 1395836 bytes read in 166 ms (8 MiB/s)
[Sat Apr 12 19:33:50.520 2014] ## Loading kernel from FIT Image at 01000000 ...
[Sat Apr 12 19:33:50.520 2014] Using 'conf@1' configuration
[Sat Apr 12 19:33:50.520 2014] Trying 'kernel@1' kernel subimage
[Sat Apr 12 19:33:50.520 2014] Description: PetaLinux Kernel
[Sat Apr 12 19:33:50.520 2014] Type: Kernel Image
[Sat Apr 12 19:33:50.520 2014] Compression: gzip compressed
[Sat Apr 12 19:33:50.520 2014] Data Start: 0x010000f0
[Sat Apr 12 19:33:50.520 2014] Data Size: 1383397 Bytes = 1.3 MiB
[Sat Apr 12 19:33:50.520 2014] Architecture: ARM
[Sat Apr 12 19:33:50.520 2014] OS: Linux
[Sat Apr 12 19:33:50.520 2014] Load Address: 0x00008000
[Sat Apr 12 19:33:50.520 2014] Entry Point: 0x00008000
[Sat Apr 12 19:33:50.520 2014] Hash algo: crc32
[Sat Apr 12 19:33:50.520 2014] Hash value: c02e0858
[Sat Apr 12 19:33:50.520 2014] Verifying Hash Integrity ... crc32+ OK
[Sat Apr 12 19:33:50.579 2014] ## Loading fdt from FIT Image at 01000000 ...
[Sat Apr 12 19:33:50.579 2014] Using 'conf@1' configuration
[Sat Apr 12 19:33:50.579 2014] Trying 'fdt@1' fdt subimage
[Sat Apr 12 19:33:50.579 2014] Description: Flattened Device Tree blob
[Sat Apr 12 19:33:50.579 2014] Type: Flat Device Tree
[Sat Apr 12 19:33:50.579 2014] Compression: uncompressed
[Sat Apr 12 19:33:50.579 2014] Data Start: 0x01151dbc
[Sat Apr 12 19:33:50.579 2014] Data Size: 11101 Bytes = 10.8 KiB
[Sat Apr 12 19:33:50.579 2014] Architecture: ARM
[Sat Apr 12 19:33:50.579 2014] Hash algo: crc32
[Sat Apr 12 19:33:50.579 2014] Hash value: 5e16707d
[Sat Apr 12 19:33:50.579 2014] Hash algo: sha1
[Sat Apr 12 19:33:50.579 2014] Hash value: 0af07559d7f0578246fb91abe17c7987dcee216a
[Sat Apr 12 19:33:50.579 2014] Verifying Hash Integrity ... crc32+ sha1+ OK
[Sat Apr 12 19:33:50.596 2014] Booting using the fdt blob at 0x1151dbc
[Sat Apr 12 19:33:50.596 2014] Uncompressing Kernel Image ... OK
[Sat Apr 12 19:33:50.692 2014] Loading Device Tree to 07ffa000, end 07fffb5c ... OK
[Sat Apr 12 19:33:50.692 2014]
[Sat Apr 12 19:33:50.692 2014] Starting kernel ...
[Sat Apr 12 19:33:50.692 2014]
[Sat Apr 12 19:33:51.298 2014] Booting Linux on physical CPU 0x0
[Sat Apr 12 19:33:51.298 2014] Linux version 3.8.11 (root@xilinx) (gcc version 4.7.3 (Sourcery CodeBench Lite 2013.05-40) ) #2 SMP PREEMPT Sat Apr 12 19:11:59 IST 2014
[Sat Apr 12 19:33:51.298 2014] CPU: ARMv7 Processor [413fc090] revision 0 (ARMv7), cr=18c53c7d
[Sat Apr 12 19:33:51.298 2014] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
[Sat Apr 12 19:33:51.298 2014] Machine: Xilinx Zynq Platform, model: Xilinx-ZC702-14.7
[Sat Apr 12 19:33:51.298 2014] Memory policy: ECC disabled, Data cache writealloc
[Sat Apr 12 19:33:51.298 2014] PERCPU: Embedded 7 pages/cpu @c0af2000 s5568 r8192 d14912 u32768
[Sat Apr 12 19:33:51.298 2014] Built 1 zonelists in Zone order, mobility grouping on. Total pages: 260096
[Sat Apr 12 19:33:51.342 2014] Kernel command line: console=ttyPS0,115200
[Sat Apr 12 19:33:51.342 2014] PID hash table entries: 4096 (order: 2, 16384 bytes)
[Sat Apr 12 19:33:51.342 2014] Dentry cache hash table entries: 131072 (order: 7, 524288 bytes)
[Sat Apr 12 19:33:51.342 2014] Inode-cache hash table entries: 65536 (order: 6, 262144 bytes)
[Sat Apr 12 19:33:51.343 2014] __ex_table already sorted, skipping sort
[Sat Apr 12 19:33:51.343 2014] Memory: 1024MB = 1024MB total
[Sat Apr 12 19:33:51.343 2014] Memory: 1036484k/1036484k available, 12092k reserved, 270336K highmem
[Sat Apr 12 19:33:51.343 2014] Virtual kernel memory layout:
[Sat Apr 12 19:33:51.343 2014] vector : 0xffff0000 - 0xffff1000 ( 4 kB)
[Sat Apr 12 19:33:51.343 2014] fixmap : 0xfff00000 - 0xfffe0000 ( 896 kB)
[Sat Apr 12 19:33:51.387 2014] vmalloc : 0xf0000000 - 0xff000000 ( 240 MB)
[Sat Apr 12 19:33:51.387 2014] lowmem : 0xc0000000 - 0xef800000 ( 760 MB)
[Sat Apr 12 19:33:51.387 2014] pkmap : 0xbfe00000 - 0xc0000000 ( 2 MB)
[Sat Apr 12 19:33:51.387 2014] modules : 0xbf000000 - 0xbfe00000 ( 14 MB)
[Sat Apr 12 19:33:51.387 2014] .text : 0xc0008000 - 0xc0208d94 (2052 kB)
[Sat Apr 12 19:33:51.387 2014] .init : 0xc0209000 - 0xc02b55c0 ( 690 kB)
[Sat Apr 12 19:33:51.387 2014] .data : 0xc02b6000 - 0xc02d3ea0 ( 120 kB)
[Sat Apr 12 19:33:51.387 2014] .bss : 0xc02d3ea0 - 0xc02e6898 ( 75 kB)
[Sat Apr 12 19:33:51.387 2014] Preemptible hierarchical RCU implementation.
[Sat Apr 12 19:33:51.387 2014] RCU restricting CPUs from NR_CPUS=4 to nr_cpu_ids=2.
[Sat Apr 12 19:33:51.435 2014] NR_IRQS:16 nr_irqs:16 16
[Sat Apr 12 19:33:51.435 2014] MIO pin 47 not assigned(00001220)
[Sat Apr 12 19:33:51.435 2014] xslcr mapped to f0002000
[Sat Apr 12 19:33:51.435 2014] Zynq clock init
[Sat Apr 12 19:33:51.435 2014] sched_clock: 16 bits at 54kHz, resolution 18432ns, wraps every 1207ms
[Sat Apr 12 19:33:51.435 2014] ps7-ttc #0 at f0004000, irq=43
[Sat Apr 12 19:33:51.435 2014] Console: colour dummy device 80x30
[Sat Apr 12 19:33:51.435 2014] Calibrating delay loop... 1332.01 BogoMIPS (lpj=6660096)
[Sat Apr 12 19:33:51.435 2014] pid_max: default: 4096 minimum: 301
[Sat Apr 12 19:33:51.435 2014] Mount-cache hash table entries: 512
[Sat Apr 12 19:33:51.435 2014] CPU: Testing write buffer coherency: ok
[Sat Apr 12 19:33:51.435 2014] CPU0: thread -1, cpu 0, socket 0, mpidr 80000000
[Sat Apr 12 19:33:51.435 2014] Setting up static identity map for 0x1b6990 - 0x1b69c4
[Sat Apr 12 19:33:51.476 2014] L310 cache controller enabled
[Sat Apr 12 19:33:51.476 2014] l2x0: 8 ways, CACHE_ID 0x000000c0, AUX_CTRL 0x72360000, Cache size: 524288 B
[Sat Apr 12 19:33:51.476 2014] CPU1: Booted secondary processor
[Sat Apr 12 19:33:51.476 2014] CPU1: thread -1, cpu 1, socket 0, mpidr 80000001
[Sat Apr 12 19:33:51.476 2014] Brought up 2 CPUs
[Sat Apr 12 19:33:51.476 2014] SMP: Total of 2 processors activated (2664.03 BogoMIPS).
[Sat Apr 12 19:33:51.476 2014] devtmpfs: initialized
[Sat Apr 12 19:33:51.476 2014] NET: Registered protocol family 16
[Sat Apr 12 19:33:51.476 2014] I reach build/linux/kernel/xlnx-3.8/source/net/socket.c:
[Sat Apr 12 19:33:51.476 2014] DMA: preallocated 256 KiB pool for atomic coherent allocations
[Sat Apr 12 19:33:51.476 2014] xgpiops e000a000.ps7-gpio: gpio at 0xe000a000 mapped to 0xf004e000
[Sat Apr 12 19:33:51.518 2014] GPIO IRQ not connected
[Sat Apr 12 19:33:51.518 2014] XGpio: /amba@0/gpio@41220000: registered, base is 255
[Sat Apr 12 19:33:51.518 2014] GPIO IRQ not connected
[Sat Apr 12 19:33:51.518 2014] XGpio: /amba@0/gpio@41200000: registered, base is 251
[Sat Apr 12 19:33:51.518 2014] usbcore: registered new interface driver usbfs
[Sat Apr 12 19:33:51.518 2014] usbcore: registered new interface driver hub
[Sat Apr 12 19:33:51.518 2014] usbcore: registered new device driver usb
[Sat Apr 12 19:33:51.518 2014] Switching to clocksource xttcps_clocksource
[Sat Apr 12 19:33:51.518 2014] e0001000.serial: ttyPS0 at MMIO 0xe0001000 (irq = 82) is a xuartps
[Sat Apr 12 19:33:51.518 2014] console [ttyPS0] enabled
[Sat Apr 12 19:33:51.534 2014] xdevcfg f8007000.ps7-dev-cfg: ioremap f8007000 to f0052000 with size 100
[Sat Apr 12 19:33:51.548 2014] xqspips e000d000.ps7-qspi: master is unqueued, this is deprecated
[Sat Apr 12 19:33:51.566 2014] m25p80 spi32766.0: found n25q128, expected n25q128
[Sat Apr 12 19:33:51.566 2014] m25p80 spi32766.0: n25q128 (16384 Kbytes)
[Sat Apr 12 19:33:51.566 2014] 4 ofpart partitions found on MTD device spi32766.0
[Sat Apr 12 19:33:51.566 2014] Creating 4 MTD partitions on "spi32766.0":
[Sat Apr 12 19:33:51.566 2014] 0x000000000000-0x000000500000 : "boot"
[Sat Apr 12 19:33:51.566 2014] 0x000000500000-0x000000520000 : "bootenv"
[Sat Apr 12 19:33:51.580 2014] 0x000000520000-0x0000006416c0 : "image"
[Sat Apr 12 19:33:51.580 2014] mtd: partition "image" doesn't end on an erase block -- force read-only
[Sat Apr 12 19:33:51.580 2014] 0x0000006416c0-0x000000a416c0 : "jffs2"
[Sat Apr 12 19:33:51.580 2014] mtd: partition "jffs2" doesn't start on an erase block boundary -- force read-only
[Sat Apr 12 19:33:51.598 2014] xqspips e000d000.ps7-qspi: at 0xE000D000 mapped to 0xF0054000, irq=51
[Sat Apr 12 19:33:51.598 2014] libphy: XEMACPS mii bus: probed
[Sat Apr 12 19:33:51.613 2014] xemacps e000b000.ps7-ethernet: invalid address, use assigned
[Sat Apr 12 19:33:51.613 2014] xemacps e000b000.ps7-ethernet: MAC updated ce:5e:a9:56:ee:44
[Sat Apr 12 19:33:51.613 2014] xemacps e000b000.ps7-ethernet: pdev->id -1, baseaddr 0xe000b000, irq 54
[Sat Apr 12 19:33:51.630 2014] ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
[Sat Apr 12 19:33:51.630 2014] ULPI transceiver vendor/product ID 0x0424/0x0007
[Sat Apr 12 19:33:51.630 2014] Found SMSC USB3320 ULPI transceiver.
[Sat Apr 12 19:33:51.630 2014] ULPI integrity check: passed.
[Sat Apr 12 19:33:51.646 2014] xusbps-ehci xusbps-ehci.0: Xilinx PS USB EHCI Host Controller
[Sat Apr 12 19:33:51.646 2014] xusbps-ehci xusbps-ehci.0: new USB bus registered, assigned bus number 1
[Sat Apr 12 19:33:51.660 2014] xusbps-ehci xusbps-ehci.0: irq 53, io mem 0x00000000
[Sat Apr 12 19:33:51.677 2014] xusbps-ehci xusbps-ehci.0: USB 2.0 started, EHCI 1.00
[Sat Apr 12 19:33:51.696 2014] hub 1-0:1.0: USB hub found
[Sat Apr 12 19:33:51.696 2014] hub 1-0:1.0: 1 port detected
[Sat Apr 12 19:33:51.696 2014] xi2cps e0004000.ps7-i2c: 400 kHz mmio e0004000 irq 57
[Sat Apr 12 19:33:51.696 2014] xadcps f8007100.ps7-xadc: enabled: yes reference: external
[Sat Apr 12 19:33:51.716 2014] xwdtps f8005000.ps7-wdt: Xilinx Watchdog Timer at f0074000 with timeout 10s
[Sat Apr 12 19:33:51.716 2014] sdhci: Secure Digital Host Controller Interface driver
[Sat Apr 12 19:33:51.716 2014] sdhci: Copyright(c) Pierre Ossman
[Sat Apr 12 19:33:51.716 2014] sdhci-pltfm: SDHCI platform and OF driver helper
[Sat Apr 12 19:33:51.736 2014] usbcore: registered new interface driver usbhid
[Sat Apr 12 19:33:51.736 2014] usbhid: USB HID core driver
[Sat Apr 12 19:33:51.736 2014] I am at build/linux/kernel/xlnx-3.8/source/drivers/hid/usbhid/hid-core.c
[Sat Apr 12 19:33:51.736 2014] VFP support v0.3: implementor 41 architecture 3 part 30 variant 9 rev 4
[Sat Apr 12 19:33:51.746 2014] Freeing init memory: 688K
[Sat Apr 12 19:33:51.759 2014]
[Sat Apr 12 19:33:51.759 2014] Hello world from myinit.c!
問題はここにあります：
[Sat Apr 12 19:33:50.692 2014] Starting kernel ...
[Sat Apr 12 19:33:50.692 2014]
[Sat Apr 12 19:33:51.298 2014] Booting Linux on physical CPU 0x0
0.6秒近くで起動が始まります。どうすれば速くできますか？ Starting kernel ...の0.1秒後に起動を開始する必要があります
これを改善するための私の焦点は何ですか？
更新
私は再び同じ問題で戻ってきました。
" カーネルを起動しています... "の後にどの関数が呼び出されるのか知りたいのですが。次のファイルにいくつかのprintfステートメントとprintkステートメントを入れましたが、現時点では何も役に立ちませんでした。
1- bootm.c
2- setup.c
3- main.c
それでも私はこれらのメッセージを持っています：
[Sat Apr 12 19:33:50.692 2014] Starting kernel ...
[Sat Apr 12 19:33:50.692 2014]
[Sat Apr 12 19:33:51.298 2014] Booting Linux on physical CPU 0x0
これらの2つのメッセージの間の時間の内訳を見つけることができません。これら2つの回線間のソフトウェア制御を知ることができたとしても、根本原因に到達するのに役立ちます。
特に、これら2つのメッセージ間で実行されているコード行を知りたいです。
これらの行の間で初期化が行われている可能性があることは知っていますが、同じコードはどこにありますか？
問題は、main（）関数がないため、上記のファイルで関数呼び出しのシーケンスを見つけることができないことです。
これらの0.6秒の間に、何かが起こります。 「Startingkernel」までのすべてのメッセージはU-Bootによって出力されます「BootingLinux」以降のすべてのメッセージはLinuxカーネルによって出力されます。カーネルは、独自のデータ構造といくつかの周辺機器を初期化する必要があります（トレースを出力するのに十分です）。これには時間がかかります。
main を読むと、カーネルが何をしているのかがわかります。 「Linuxの起動」メッセージは smp_setup_processor_idへの呼び出し から送信されます。
デバッガーでコードをトレースして、どこで時間を費やしているかを確認できます。たとえば、初期化されている不要なハードウェアがいくつかある可能性があります。しかし、現時点で何かを得る可能性は低いです。
これは、ブートローダーとカーネルのあり方と関係があると思いますglued。 HallinanのEmbeddedLinux Primerのセクション5.1.3（Bootstrap Loader）には、次のように書かれています。
一部のbootstrapローダーはカーネルイメージのチェックサム検証を実行し、ほとんどのローダーはカーネルイメージを解凍して再配置します。このコンテキストでのブートローダーとbootstrapローダーの違いシンプル：ブートローダーは電源投入時にボードを制御し、Linuxカーネルにまったく依存しません。対照的に、bootstrapローダーの主な目的は、ベア間の接着剤として機能することです。金属製のブートローダーとLinuxカーネル。カーネルを実行するための適切なコンテキストを提供し、カーネルのバイナリイメージを解凍して再配置するために必要な手順を実行するのは、bootstrapローダーの責任です。
それを含む画像を見ると、カーネルが実際に実行される前に、head.sおよびhead-<Arch>.sアセンブリルーチンが実行されます。カーネルはカーネル固有形式（vmlinux）ではなく、これらのルーチンに圧縮および接着であるため、メモリへのカーネル解凍などの他のタスクを実行する必要があります。として piggy.gz画像。
これはArch固有ですが、Ubootからカーネルへの切り替えの間に余分な時間がかかる可能性があると思います。
do_bootm_linuxの関数bootm.cから始めて、コードに進みます。カーネルの起動時にパラメータdebugまたはloglevel=7を追加して、詳細情報を取得することもできます。