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Re: Trying to get an embedded C function to use file I/O
- From: fche at redhat dot com (Frank Ch. Eigler)
- To: Jeff Johnston <jjohnstn at redhat dot com>
- Cc: systemtap at sourceware dot org
- Date: Mon, 19 Aug 2013 18:02:12 -0400
- Subject: Re: Trying to get an embedded C function to use file I/O
- References: <520E645A dot 9080305 at redhat dot com> <y0mli3zc20t dot fsf at fche dot csb> <52124A10 dot 4020504 at redhat dot com>
jjohnstn wrote:
> [...] The LTTng kernel side of the trace ends up with multiple CTF
> format files: a metadata file which describes the data format and a
> number of binary files (essentially a permutation of CPUs and
> channels (usually just channel 0). [...]
Is lttng restricted to having only a single 'channel' or dataset per
file? If not, why not
(a) have one monster CTF file that includes cross-cpu cross-channel
cross-everything data?
or
(b) use stap -b (bulk) mode to produce per-cpu files, each of which
could be converted to CTF in userspace (perhaps requiring nothing
but removal of the stap timestamping/framing metadata in those
bulk-mode files; see stap-merge.c).
- FChE