On 2015/4/24 21:58, David Ahern wrote: > On 4/24/15 7:31 AM, Yunlong Song wrote: >> Now we are profiling the performance of ext4 and f2fs on an eMMC card with >> iozone, >> we find a case that ext4 is better than f2fs in random write under the test >> of >> "iozone -s 262144 -r 64 -i 0 -i 2". We want to analyze the I/O delay of the >> two >> file systems. We have got a conclusion that 1% of sys_write takes up 60% >> time of >> the overall sys_write (262144/64=4096). We want to find out the call stack >> during >> this specific 1% sys_write. Our idea is to record the stack in a certain >> time period >> and since the specific 1% case takes up 60% time, the total number of >> records of its >> stack should also takes up 60% of the total records, then we can recognize >> those stacks >> and figure out what the I/O stack of f2fs is doing in the 1% case. > > And to address this specific profiling problem have you tried: > > perf trace record -- iozone ... > perf trace -i perf.data -S > > > >
But this only shows the system call like strace, but we want the call stack of kernel functions in fact. -- Thanks, Yunlong Song -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
