Notes from stap meeting 20060803

[Elena Zannoni <ezannoni at redhat dot com>]

Will took notes this time

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kprobes portion-------------

userspace probes
	attaching on two fronts:
	-modified version from spring (prassana addressing issues)
	-utrace other approach (jim and ananth working on that of/on)

some effort testing utrace on s390
need priorities  in notify structure maybe put into utrace
some issues building utrace testing structures
any request to test utrace on ppc64 from redhat?
dave wilder doing some testing, gdb on ptrace on utrace ppc64
performance measurements on userspace probes approaches
	-still need to doing measurements on utrace

someone (anil?) is working on ia64 utrace
Need to agree on which tests to run for utrace testing
	i386/x86_64 redhat (what is rh doing for testing?)
	ia64 intel
	ppc64/s390 ibm
what is plan to get utrace upstream?


bz2091 why failing only on some power64 architectures

bug with itrace similar works on power5, crashes on power4
	mike mason looking at this


systemtap--------------------

redhat: david, will, elena
ibm: jim, david wilder
intel: josh


talked about inviting Mathieu Desnoyes


s390 kprobes should be in rawhide, hasn't been tested
dave wilder will test

any news about userspace probes?
working on getting gdb fixed with utrace
roland has a number of patches to clean things up
need to rerun tests
run tests in gdb source, might need to compare utrace results with 
ptrace run

anil has been testing utrace ia64
elena says utrace incomplete on ia64, need some additional work
frysk uses other parts of utrace, and gdb testing single threaded
is there an strace testsuite?

userspace probes?
prasanna persuing the two approaches.
prasanna has done some perf testing of earlier approach
nothing on utrace implementation
what are chances of getting into rhel5 in the next month?
	gate is closing on rhel5. might get a few features in
have something that works (prasanna approach)
	no code review in 3/4 weeks
	less politically acceptable than utrace approach (jim)
	want to know what kabis these patches will break

dave smith: cross compilation support module location information
	resubmitted kernel patch, and got comments on it.
	will submit upstream
	what about testing it? need two machines?
	also working on probe merge patch
		can low module size significantly

will cohen:
	success on i686 xen running of systemtap tests
	discussion with stephane eranian about perfmon2 testing
	perfmon2 systemtap
	

frank eigler:
	moving testsuite into same package
	adding examples into wiki

josh stone:
	trying to get xen working
	x86-64 both seems to work xen
	timer.profile doesn't work (dynamic ticks) need to investigate
	should xen get the registration to fail?
	or have on dynamic tick code path
	oprofile uses same hook, Will Cohen should check works

bryan
	working on dashboard, collection of scripts other people found useful
	dashboard for new users
	eager to get additional scripts
	how does gui chart data, documentation on this? uses regex

static kernel markers
	frank: has there been any progress been porting block trace code
		to static marker
	satoshi: mentions static probe mechanism still have to be careful
		with changing code at static marker. could cause fault
	frank: no changes in code space to avoid these problems
	tomz: where to get code to do this? stap_mark.h in systemtap
		documented in man page? also described in ols paper
	vara: do we want to put static tracing in rhel5?
		frank doesn't see it happening

satoshi: lastest rawhide kernel	split of debuginfo. which rpms are required?
	yum install just the "kernel package name" -debuginfo