Messages in this thread | | | Date | Thu, 16 Dec 2010 00:02:45 +1100 | From | Nick Piggin <> | Subject | Re: buggy perf callgraph output |
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On Wed, Dec 08, 2010 at 10:48:13PM +0100, Frederic Weisbecker wrote: > I can not reproduce it. Could you please try to reproduce, > run perf archive and send me your perf.data.tar.bz2 ?
It seems to be happening all the time, just look further in callgraphs.
This attached perf.data.bz2 looks like this, when using -g graph
15.05% dbench [kernel.kallsyms] [k] copy_user_generic_string | --- copy_user_generic_string | |---0.16%-- generic_file_aio_read | do_sync_read | vfs_read | | | --0.05%-- sys_pread64 | system_call | 0x7f64a60bb193 | |--0.10%-- generic_file_buffered_write | __generic_file_aio_write | generic_file_aio_write | do_sync_write | vfs_write | sys_pwrite64 | system_call | 0x7f64a60bb203 | 0xe01170 | ---0.11%-- dcache_readdir vfs_readdir sys_getdents system_call 0x7f64a60ade65
See, the last element is greater than the second last.
-g fractal looks like this:
15.05% dbench [kernel.kallsyms] [k] copy_user_generic_string | --- copy_user_generic_string | |---1.09%-- generic_file_aio_read | do_sync_read | vfs_read | | | |--0.55%-- sys_pread64 | | system_call | | 0x7f64a60bb193 | | | --2.19%-- sys_read | system_call | 0x7f64a60d3ea0 | |--0.69%-- generic_file_buffered_write | __generic_file_aio_write | generic_file_aio_write | do_sync_write | vfs_write | sys_pwrite64 | system_call | 0x7f64a60bb203 | 0xe01170 | |---0.72%-- dcache_readdir | vfs_readdir | sys_getdents | system_call | 0x7f64a60ade65
So it's totally screwy.
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