Tracepoint: evaluate arguments within test block

> On Thu, 2011-11-17 at 04:55 +0100, Eric Dumazet wrote:
> > The general admitted claim of a tracepoint being on x86 a single
> > instruction :
> >
> > jmp +0
> >
> > Is not always true.
> >
> > For example in mm/slub.c, kmem_cache_alloc()
> >
> > void *ret = slab_alloc(s, gfpflags, NUMA_NO_NODE, _RET_IP_);
> > trace_kmem_cache_alloc(_RET_IP_, ret, s->objsize, s->size, gfpflags);
> > return ret;
> >
> > We can check compiler output and see that 4 extra instructions were
> > added because s->objsize & s->size are evaluated.
> >
> > I noticed this in a perf session, because these 4 extra instructions
> > added some noticeable latency/cost.
> >
> > c10e26a4:       8b 5d d8                mov    -0x28(%ebp),%ebx
> > c10e26a7:       85 db                   test   %ebx,%ebx
> > c10e26a9:       75 6d                   jne    c10e2718   (doing the memset())
> > c10e26ab:       8b 76 0c                mov    0xc(%esi),%esi   // extra 1
> > c10e26ae:       8b 5d 04                mov    0x4(%ebp),%ebx   // extra 2
> > c10e26b1:       89 75 f0                mov    %esi,-0x10(%ebp) // extra 3
> > c10e26b4:       89 5d ec                mov    %ebx,-0x14(%ebp) // extra 4
> > c10e26b7:       e9 00 00 00 00          jmp    c10e26bc
> > c10e26bc:       8b 45 d8                mov    -0x28(%ebp),%eax
> > c10e26bf:       83 c4 28                add    $0x28,%esp
> > c10e26c2:       5b                      pop    %ebx
> > c10e26c3:       5e                      pop    %esi
> > c10e26c4:       5f                      pop    %edi
> > c10e26c5:       c9                      leave
> >
> >
> > A fix would be to not declare an inline function but a macro...
> >
> > #define trace_kmem_cache_alloc(...) \
> >     if (static_branch(&__tracepoint_kmem_cache_alloc.key)) \
> >             __DO_TRACE(&__tracepoint_kmem_cache_alloc,      \
> >                     ...
> >
> > Anyone has some clever idea how to make this possible ?

Do this by moving the test into the tracepoint() macro.

Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Remove console output that should be turned into debug

But no debug log facility for this library which is included in
sessiond (yet).

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Document LGPL TRACEPOINT_CREATE_PROBES restrictions

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

tracepoint: support TP_ARGS(void)

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix multiple probe generation into one single C file

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Remove run from makefile

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add demo program

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Allow release object to have -1 sock param

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

initiate lttng-ust-comm printout cleanup

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix fork handling, where child shares shm with parent

Consider that consumer does most of the finalize/flush, so we don't need
to perform them in teardown.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Remove unused libringbuffer/ring_buffer_abi.c

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Update comment

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Tracepoint API change: combine TP_PROTO and TP_VARS into TP_ARGS, remove _NOARGS macros

New API for tracepoints, combining the TP_PROTO and TP_VARS arguments
into a single "TP_ARGS" macro. It takes up to 10 parameters (from 0 to
10). The "_NOARGS" special-case is not needed anymore: it can be
achieved simply by passing an empty TP_ARGS:

  TP_ARGS(),

to the standard tracepoint event declarations.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Tracepoints: add provider mismatch check

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Tracepoint API change: rename TRACEPOINT_SYSTEM to TRACEPOINT_PROVIDER

Eliminates the confusion between the first TRACEPOINT_EVENT "provider"
argument and the "TRACEPOINT_SYSTEM", which need to be the same thing.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Merge branch 'master' of git.lttng.org:/home/git/lttng-ust

tracepoint API change: rename TP_ARGS to TP_VARS

In preparation of folding of both TP_PROTO and TP_ARGS into TP_ARGS.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

lttng-ust-comm: relicense to LGPLv2.1

This internal communication library is used by both lttng-sessiond and
lttng-ust. lttng-ust is LGPLv2.1, so we need to make this library
LGPLv2.1 to ensure licensing is respected.

However, we now keep this library internal to liblttng-ust and
liblttng-ust-ctl. It is not installed into the system anymore. Only the
lttng-sessiond (or another GPLv2-compatible session daemon) is meant to
control liblttng-ust through the GPLv2 liblttng-ust-ctl control library.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: David Goulet <david.goulet@polymtl.ca>
Signed-off-by: Julien Desfossez <julien.desfossez@polymtl.ca>

Do not install liblttng-ust-comm and ust-comm.h

Only used internally by liblttng-ust-ctl and liblttng-ust.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix metadata tp listing filtering

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Don't list metadata tracepoint

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add delay parameter to hello test program

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Define ltt_transport_list as static

Fix uninitialized state at constructor execution.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Clean unused vars. warnings

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add missing core.c file

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Implement ustctl_tracepoint_list/list_get

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Implement LTTNG_UST_TRACEPOINT_LIST

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

update char limit comment in tracepoint

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Move libringbuffer and comm connect messages to debug level

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Tracepoint API change: add provider field

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

init private data

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Move struct ltt_channel to shm for consumer flush

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix problem with including libringbuffer/smp.h in make-dist

"make dist" currently produces a tarball that is missing
librinbuffer/smp.h, resulting in a build failure when an attempt to
compile the tarball is make.  This patch addresses the issue by properly
including the file in Makefile.am.

Signed-off-by: Gregory Haskins <gregory.haskins@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix shadow channel struct callback override in consumer

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Allow consumer to flush buffers, fix alignment bug

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

flush buffer returns void

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Zero out callback pointers in consumer process

They cannot be used anyway.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Allow flush buffer for inactive producer (flush mode)

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Update flush buffer: allow consumer to do it directly

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

fix make dist: adding missing headers to makefiles

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix make dist: check if java lib should be built in toplevel makefile too

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix make dist dep for tests/hello

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add missing headers to install to makefile.am

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add missing header

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

install processor.h, needed by core.h

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add check for libuuid to configure.ac

libuuid is needed by the ring-buffer library.

Signed-off-by: Alexandre Montplaisir <alexandre.montplaisir@polymtl.ca>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Rename ust.pc.in to lttng-ust.pc.in

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Update local comm socket path

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Update lttng-sessiond communication socket path

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Rename UST.class to LTTNG_UST.class

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Rename package to lttng-ust

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

library mass rename: add lttng- prefix

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Update readme

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Move include/ust/ to include/lttng/

Keep all lttng project files under the same toplevel directory.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add lttng_ust_ prefix before objd_unref

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add lttng_ust prefix before struct obj and struct objd_ops

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Rename ltt_events_exit to lttng_ust_events_exit

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Update to use caa_likely/caa_unlikely from urcu 0.6.6

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Rename struct lib_ring_buffer* to struct lttng_ust_lib_ring_buffer*

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Rename shm_handle to lttng_ust_shm_handle

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Move lttng_ust_object_data et lttng_ust_channel_attr to -abi.h

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

rename object_data to lttng_ust_object_data

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

futex error should be a warning

* Matthew Khouzam (matthew.khouzam@ericsson.com) wrote:
> Hi tracing warlords,
> I am testing UST 2.0 on ubuntu Lucid Lynx, and I got the following
> message while running a program:
> libust[22376/22377]: Error: Linux kernels 2.6.33 to 3.0 (with the
> exception of stable versions) do not support FUTEX_WAKE on read-only
> memory mappings correctly. Please upgrade your kernel (fix is commit
> 9ea71503a8ed9184d2d0b8ccc4d269d05f7940ae in Linux kernel mainline).
> LTTng-UST will use polling mode fallback. (in wait_for_sessiond() at
> lttng-ust-comm.c:564)
>
> I think since there is a fallback, and this is not a showstopper just an
> irritation that it should be a warning.

Reported-by: Matthew Khouzam <matthew.khouzam@ericsson.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Remove duplicate prototype declaration

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add context to both channel and event

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

change start/stop session parameters

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

standardize on flush buffer (no plural)

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add flush buffers command

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Implement ustctl_register_done

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Install UST comm lib

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix missing logging symbols

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add get mmap base

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add ustctl_open_stream_read and ustctl_close_stream_read

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Implement ustctl_unmap_channel()

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add lttng-ust-ctl.h header

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Implement libustctl

We privatise libringbuffer (not installed anymore), exposing a cleaner
API (libustctl) instead. This API will be used by the lttng-tools UST
consumer.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Remove empty line from tracepoint.h

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Do not install libringbuffer into system

This is not meant to be a stable API. We'll provide a convenient wrapper
over it instead.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add powerpc64 host_cpu to configure.ac

Seems like autoconf uses powerpc64 as our host cpu type, this
patch is to fix build issues in openembedded/yocto targets.

Signed-off-by: Matthew McClintock <msm@freescale.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add procname context

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add vpid context

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Reset vtid after fork in child

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add vtid (gettid()) context

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add pthread id event context

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Update error check for root handle

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Remove root handle asssert: can differ from 0 if many sessiond

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix cmsg handling

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Cleanup: fix strict aliasing ion tests

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Cleanup warnings

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Cleanup warnings

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add multi session, multi-channel test

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add ust basic tracing implementation

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add ust basic tracing daemon

single process, single session, single channel

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add pthread id context

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Only select efficient unaligned accesses for x86 and powerpc

This is why the Linux kernel does at this point.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Use unaligned writes for arch with efficient unaligned accesses

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Use network byte order field in hello test

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

tests: Add a long field

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add missing alignment after header write

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

lttng tracepoint event: don't clash with "ctx" argument name

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>