I need trace python projects, with low over head and a little flexibility. There are some pure python based trace tools, but most of them make codes slower. I also tried systemtap, but it still become much slower in complicated python codes. I'm now finding a better tool or some inspirations.
Flexibility for me means that operators could write some scripts to choose what to trace. Someone traces function A, and someone traces B for other purposes. Using the android case as example, I think I could control the format of input data to manage trace objects. However I'm not confident with this idea. On Wed, Aug 12, 2015 at 11:58 AM, Scotty <sba...@eng.utah.edu> wrote: > Hi Kun, > > > > On 08/11/2015 08:42 PM, Kun Huang wrote: >> Hi Scotty >> >> I have read your links. I found the read from 'trace' and the write to >> 'trace_marker' are normal read&write which works like proc system. >> >> I have questions that what's more difference between ftrace and proc? >> I just know I could read data as pipeline from ftrace. > > Well, in kernel land you can trace your functions, with very little over > head. For example, in the binder driver > (http://lxr.free-electrons.com/source/drivers/android/binder.c#L2423) there > are trace events everywhere throughout the code. The thing is you need to > build the traces into your code, if you're going to use it. > > When you're in userland one way to trace your application flow is by making a > wrapper around the debugfs entry (like android does) and manually write()'ing > the data into the kernel buffer -- This is what android does. > > Why ftrace is in debugfs and not procfs? I'm not sure you'll have to ask the > original developers, I'm sure there is a good reason. > > Perhaps I didn't understand your use case. Did you want to see what was > happening in kernel land while you were running your python project? Or do > you want to be able to trace your python functions like the way ftrace can > trace kernel functions during execution? > > > > >> On Wed, Aug 12, 2015 at 10:25 AM, Kun Huang <gar...@openstacker.org> wrote: >>> Thank you for your help Scotty :) I'm reading it. >>> >>> On Wed, Aug 12, 2015 at 2:34 AM, Scotty Bauer <sba...@eng.utah.edu> wrote: >>>> It is possible to trace from userland, Android does it. >>>> >>>> Essentially you need to write your data into >>>> /sys/kernel/debug/tracing/trace_marker >>>> >>>> then read it out of /sys/kernel/debug/tracing/trace >>>> >>>> >>>> If you care how the implementation works you can read it in >>>> /kernel/tracing/trace.c >>>> (http://lxr.free-electrons.com/source/kernel/trace/trace.c) search for >>>> tracing_mark_fops and tracing_fops. >>>> >>>> >>>> In Android here are the relevant files you will need to see how it's used >>>> in >>>> userland: >>>> Atrace (for reading data out + setting things up): >>>> https://android.googlesource.com/platform/frameworks/native/+/master/cmds/atrace/atrace.cpp >>>> https://android.googlesource.com/platform/external/chromium-trace/+/master >>>> (host side setup of the device) >>>> >>>> trace-dev (for writing data in): >>>> https://android.googlesource.com/platform/system/core/+/master/libcutils/trace-dev.c >>>> >>>> Once we have all the data we usually run it through trace-viewer, >>>> (https://github.com/catapult-project/catapult) >>>> >>>> Cheers. >>>> >>>> >>>>> On 2015-08-11 06:53, Kun Huang wrote: >>>>>> >>>>>> Hi ftrace developers >>>>>> >>>>>> I'm developing a huge python based programs and facing performance >>>>>> issue everyday. I like the ftrace system and hope there could be a >>>>>> tracer to trace&report my python codes. Is it possible or is it >>>>> >>>>> worthy >>>>>> >>>>>> to do this? >>>>>> >>>>>> --- >>>>>> >>>>>> Kun >>>>>> -- >>>>>> 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 >>>>> >>>>> [6] >>>>>> >>>>>> Please read the FAQ at http://www.tux.org/lkml/ [7] >>>>> >>>>> >>>>> Links: >>>>> ------ >>>>> [1] http://lxr.free-electrons.com/source/kernel/trace/trace.c >>>>> [2] >>>>> >>>>> https://android.googlesource.com/platform/frameworks/native/+/master/cmds/atrace/atrace.cpp >>>>> [3] >>>>> https://android.googlesource.com/platform/external/chromium-trace/+/master >>>>> [4] >>>>> >>>>> https://android.googlesource.com/platform/system/core/+/master/libcutils/trace-dev.c >>>>> [5] https://github.com/catapult-project/catapult >>>>> [6] http://vger.kernel.org/majordomo-info.html >>>>> [7] http://www.tux.org/lkml/ >> -- >> 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/ >> -- 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/
