we can use intel processor trace facility since cpu power on
so we can try this patch to do early code analysis at basic block
level.
The basic usage is as below:
#./sptdump
#./sptdecode --pt ptout.0 -e ../linux-test/vmlinux | less
....
[+ 10] ext4_getblk+159 -> __getblk_gfp
[+ 13] __getblk_gfp+30 -> __find_get_block
[+ 112] __find_get_block+167 ->
mark_page_accessed
[+ 2] __getblk_gfp+38 -> _cond_resched
[+ 7] _cond_resched+16 -> rcu_all_qs
[+ 35] htree_dirblock_to_tree+324 ->
__ext4_check_dir_entry
[+ 8] htree_dirblock_to_tree+352 -> ext4fs_dirhash
[+ 53] ext4fs_dirhash+196 -> str2hashbuf_signed
[+ 18] htree_dirblock_to_tree+233 ->
ext4_htree_store_dirent
[+ 18] ext4_htree_store_dirent+52 -> __kmalloc
[+ 10] __kmalloc+27 -> kmalloc_slab
[+ 9] __kmalloc+248 -> _cond_resched
[+ 7] _cond_resched+16 -> rcu_all_qs
[+ 39] __kmalloc+303 -> __memset
[+ 4] __kmalloc+231 -> memcg_kmem_put_cache
[+ 17] ext4_htree_store_dirent+114 -> __memcpy
[+ 14] ext4_htree_store_dirent+214 ->
rb_insert_color
[+ 26] htree_dirblock_to_tree+324 ->
__ext4_check_dir_entry
[+ 8] htree_dirblock_to_tree+352 -> ext4fs_dirhash
[+ 53] ext4fs_dirhash+196 -> str2hashbuf_signed
[+ 18] htree_dirblock_to_tree+233 ->
ext4_htree_store_dirent
[+ 18] ext4_htree_store_dirent+52 -> __kmalloc
[+ 10] __kmalloc+27 -> kmalloc_slab
[+ 9] __kmalloc+248 -> _cond_resched
....
The patch borrows some idea/code and tools from Andi Kleen's
simple-pt project.
Luming Yu(9):
Basic support for early intel processor trace features with zero deps
boot option early_pt to enable early pt
boot option early_pt_buf_len for early pt buffer size setup
early pt basic addr pair filter support (addr0 && addr1)
early pt basic addr pair filter support (addr0 && addr1)
early pt enable mtc freq packet
enable early pt psb packet
early pt enable cyc packet
start early intel processor trace in early boot
arch/x86/events/Kconfig | 6 +
arch/x86/events/intel/Makefile | 1 +
arch/x86/events/intel/early_pt.c | 443 +++++++++++++++++++++++++++++++++++++++
arch/x86/kernel/smpboot.c | 2 +
init/main.c | 2 +
kernel/trace/Kconfig | 2 +-
6 files changed, 455 insertions(+), 1 deletion(-)
create mode 100644 arch/x86/events/intel/early_pt.c
--
2.7.5
