Need help to understand system calls
Hello all, I am running the Iozone benchmark commands to find disk characteristics on my system and trying to construct a call graph for the iozone functions. I am using perf tools to generate a call graph , but I am having trouble understanding the output from the perf commands as follows-- # Events: 62K cpu-clock # # Overhead Command Shared Object Symbol # ........ .............. .......................... .............................................................................................................................. # 79.23% swapper [kernel.kallsyms] [k] native_safe_halt | --- native_safe_halt default_idle cpu_idle start_kernel x86_64_start_kernel 4.99% iozone [kernel.kallsyms] [k] copy_user_generic_unrolled | --- copy_user_generic_unrolled iov_iter_copy_from_user_atomic generic_perform_write generic_file_buffered_write __generic_file_aio_write generic_file_aio_write ext4_file_write do_sync_write vfs_write sys_write ia32_sysret 0xf77904be __write_nocancel I need to understand these kernel commands , kindly give some pointers for the same. Are there any resources available online ?? I am attaching the complete file along with the mail. Thanks and regards, *Nitisha*
On Tue, Jul 16, 2013 at 2:48 PM, Nitisha Jain <nitishajain15@gmail.com> wrote:
Hello all,
I am running the Iozone benchmark commands to find disk characteristics on my system and trying to construct a call graph for the iozone functions. I am using perf tools to generate a call graph , but I am having trouble understanding the output from the perf commands as follows--
exactly, what is your confusion? -- regards, Mulyadi Santosa Freelance Linux trainer and consultant blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com
My confusion is how to interpret this output from perf , what are copy_user_generic_unrolled and native_safe_halt for instance ? I have profiled iozone benchmark using other tools like gprof and callgrind and they show me the actual functions being called by iozone as apparent from the source code. But what is this perf output showing me then ? Are generic_file_buffered_write , ext4_file_write etc all system calls ? On Thu, Jul 25, 2013 at 2:59 PM, Mulyadi Santosa <mulyadi.santosa@gmail.com>wrote:
On Tue, Jul 16, 2013 at 2:48 PM, Nitisha Jain <nitishajain15@gmail.com> wrote:
Hello all,
I am running the Iozone benchmark commands to find disk characteristics on my system and trying to construct a call graph for the iozone functions. I am using perf tools to generate a call graph , but I am having trouble understanding the output from the perf commands as follows--
exactly, what is your confusion?
-- regards,
Mulyadi Santosa Freelance Linux trainer and consultant
blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com
-- Thanks and regards, *Nitisha Jain* 9483004565
participants (3)
-
Mulyadi Santosa -
Nitisha Jain -
Valdis.Kletnieks＠vt.edu