On 11/18/2013 08:59 AM, Amit Margalit wrote: > Hi, > > I understand, and I see two issue with this - > > 1. The application will still perform all the tracking, but when the > event is to be generated, it will be checked and since it is > disabled, will not be emitted. > While the overhead of checking whether the event is enabled is > indeed minimal, the overhead of tracking existing state, is not > negligible - it includes code, data and CPU cycles. > 2. I believe that the average user will simply want to use > "enable-event -u -a" or similar, and should not care about later > disabling these specific events. > > > I believe this ought to be a compile-time option, and I don't mind if > it defaults to "Enabled"...
How about an environment variable (e.g. LTTNG_UST_WITHOUT_BADDR_STATEDUMP) that suppresses base address state tracing. Would that be of value to you ? -- Best, Paul > > What do you think? > > Amit Margalit > IBM XIV - /Storage Reinvented/ > XIV-NAS Development Team > Tel. 03-689-7774 > Fax. 03-689-7230 > > > > From: Mathieu Desnoyers <[email protected]> > To: Amit Margalit/Israel/IBM@IBMIL > Cc: [email protected], Paul Woegerer > <[email protected]> > Date: 11/17/2013 04:02 PM > Subject: Re: [lttng-dev] [PATCH v3 2/2] Implement > base-address-state tracing > ------------------------------------------------------------------------ > > > > ------------------------------------------------------------------------ > > *From: *"Amit Margalit" <[email protected]>* > To: *"Mathieu Desnoyers" <[email protected]>* > Cc: *[email protected], "Paul Woegerer" > <[email protected]>* > Sent: *Sunday, November 17, 2013 4:36:19 AM* > Subject: *Re: [lttng-dev] [PATCH v3 2/2] Implement base-address-state > tracing > > I guess I missed something in the discussion - is this going to be > active all the time, or can I disable it somehow? > > Maybe a command-line switch to turn this off? > > For me this is overhead that I don't need and don't want. > > You just have to not enable those new events if you don't care about > them. > > Thanks, > > Mathieu > > > Thanks, > > Amit Margalit > IBM XIV - /Storage Reinvented/ > XIV-NAS Development Team > Tel. 03-689-7774 > Fax. 03-689-7230 > > > > From: Mathieu Desnoyers <[email protected]> > To: Paul Woegerer <[email protected]> > Cc: [email protected] > Date: 11/14/2013 09:30 PM > Subject: Re: [lttng-dev] [PATCH v3 2/2] Implement > base-address-state tracing > ------------------------------------------------------------------------ > > > > ----- Original Message ----- > > From: "Paul Woegerer" <[email protected]> > > To: [email protected], "mathieu desnoyers" > <[email protected]> > > Sent: Thursday, November 14, 2013 1:39:49 PM > > Subject: [PATCH v3 2/2] Implement base-address-state tracing > > > > Dump the base-address state (executable and shared objects) into session > > on session-enable (per-session events). > > Merged, thanks ! > > Mathieu > > > > > Signed-off-by: Paul Woegerer <[email protected]> > > --- > > include/lttng/ust-tracepoint-event.h | 14 +++++++ > > liblttng-ust-baddr/Makefile.am | 4 +- > > liblttng-ust-baddr/lttng-ust-baddr.c | 72 > > ++++++++++++++++++++++++++++++++ > > liblttng-ust-baddr/ust_baddr_statedump.c | 21 ++++++++++ > > liblttng-ust-baddr/ust_baddr_statedump.h | 60 > ++++++++++++++++++++++++++ > > liblttng-ust/lttng-events.c | 2 + > > liblttng-ust/lttng-tracer-core.h | 3 ++ > > liblttng-ust/lttng-ust-comm.c | 60 > ++++++++++++++++++++++++++ > > 8 files changed, 235 insertions(+), 1 deletion(-) > > create mode 100644 liblttng-ust-baddr/ust_baddr_statedump.c > > create mode 100644 liblttng-ust-baddr/ust_baddr_statedump.h > > > > diff --git a/include/lttng/ust-tracepoint-event.h > > b/include/lttng/ust-tracepoint-event.h > > index bb3a05d..be58030 100644 > > --- a/include/lttng/ust-tracepoint-event.h > > +++ b/include/lttng/ust-tracepoint-event.h > > @@ -480,6 +480,18 @@ size_t > > __event_get_align__##_provider##___##_name(_TP_ARGS_PROTO(_args)) \ > > #define TP_FIELDS(...) __VA_ARGS__ > > > > /* > > + * For state dump, check that "session" argument (mandatory) > matches the > > + * session this event belongs to. Ensures that we write state dump > data only > > + * into the started session, not into all sessions. > > + */ > > +#undef _TP_SESSION_CHECK > > +#ifdef TP_SESSION_CHECK > > +#define _TP_SESSION_CHECK(session, csession) (session == csession) > > +#else /* TP_SESSION_CHECK */ > > +#define _TP_SESSION_CHECK(session, csession) 1 > > +#endif /* TP_SESSION_CHECK */ > > + > > +/* > > * Using twice size for filter stack data to hold size and pointer for > > * each field (worse case). For integers, max size required is 64-bit. > > * Same for double-precision floats. Those fit within > > @@ -506,6 +518,8 @@ void > > __event_probe__##_provider##___##_name(_TP_ARGS_DATA_PROTO(_args)) > \ > > > > \ > > if (0) > > \ > > (void) __dynamic_len_idx; > /* don't warn if unused */ \ > > + if (!_TP_SESSION_CHECK(session, __chan->session)) > \ > > + return; > > \ > > if > (caa_unlikely(!CMM_ACCESS_ONCE(__chan->session->active))) > \ > > return; > > \ > > if > (caa_unlikely(!CMM_ACCESS_ONCE(__chan->enabled))) > \ > > diff --git a/liblttng-ust-baddr/Makefile.am > b/liblttng-ust-baddr/Makefile.am > > index afa9489..0d3cf28 100644 > > --- a/liblttng-ust-baddr/Makefile.am > > +++ b/liblttng-ust-baddr/Makefile.am > > @@ -5,7 +5,9 @@ lib_LTLIBRARIES = liblttng-ust-baddr.la > > liblttng_ust_baddr_la_SOURCES = \ > > lttng-ust-baddr.c \ > > ust_baddr.c \ > > - ust_baddr.h > > + ust_baddr.h \ > > + ust_baddr_statedump.c \ > > + ust_baddr_statedump.h > > liblttng_ust_baddr_la_LIBADD = \ > > -L$(top_builddir)/liblttng-ust/.libs \ > > -llttng-ust > > diff --git a/liblttng-ust-baddr/lttng-ust-baddr.c > > b/liblttng-ust-baddr/lttng-ust-baddr.c > > index f24a171..a856965 100644 > > --- a/liblttng-ust-baddr/lttng-ust-baddr.c > > +++ b/liblttng-ust-baddr/lttng-ust-baddr.c > > @@ -34,6 +34,7 @@ > > > > #define TRACEPOINT_DEFINE > > #include "ust_baddr.h" > > +#include "ust_baddr_statedump.h" > > > > int > > lttng_ust_push_baddr(void *so_base, const char *so_name) > > @@ -62,3 +63,74 @@ lttng_ust_pop_baddr(void *so_base) > > tracepoint(ust_baddr, pop, so_base); > > return 0; > > } > > + > > +static int > > +extract_soinfo_events(struct dl_phdr_info *info, size_t size, void > *data) > > +{ > > + int j; > > + int num_loadable_segment = 0; > > + > > + for (j = 0; j < info->dlpi_phnum; j++) { > > + char resolved_path[PATH_MAX]; > > + struct stat sostat; > > + void *base_addr_ptr; > > + > > + if (info->dlpi_phdr[j].p_type != > PT_LOAD) > > + continue; > > + > > + /* Calculate virtual memory > address of the loadable segment */ > > + base_addr_ptr = (void *) > info->dlpi_addr > > + + > info->dlpi_phdr[j].p_vaddr; > > + > > + num_loadable_segment += 1; > > + if ((info->dlpi_name == NULL || > info->dlpi_name[0] == 0) > > + > && num_loadable_segment == 1) { > > + /* > > + * If the > iterated element is the executable itself we > > + * have to use > Dl_info to determine its full path > > + */ > > + Dl_info dl_info > = { 0 }; > > + if > (!dladdr(base_addr_ptr, &dl_info)) > > + > return 0; > > + if > (!realpath(dl_info.dli_fname, resolved_path)) > > + > return 0; > > + } else { > > + /* > > + * For regular > dl_phdr_info entries we have to check if > > + * the path to > the shared object really exists > > + */ > > + if > (!realpath(info->dlpi_name, resolved_path)) { > > + > /* Found vDSO, put the 'path' into brackets */ > > + > snprintf(resolved_path, PATH_MAX - 1, "[%s]", > > + > info->dlpi_name); > > + } > > + } > > + > > + if (stat(resolved_path, &sostat)) { > > + sostat.st_size = 0; > > + sostat.st_mtime > = -1; > > + } > > + > > + tracepoint(ust_baddr_statedump, > soinfo, > > + > (struct lttng_session *) data, base_addr_ptr, > > + > resolved_path, sostat.st_size, sostat.st_mtime); > > + > > + /* > > + * We are only interested in the > base address (lowest virtual > > + * address associated with the > memory image), skip the rest > > + */ > > + break; > > + } > > + return 0; > > +} > > + > > +int > > +lttng_ust_baddr_statedump(struct lttng_session *session) > > +{ > > + /* > > + * Iterate through the list of currently loaded > shared objects and > > + * generate events for loadable segments using > extract_soinfo_events > > + */ > > + dl_iterate_phdr(extract_soinfo_events, session); > > + return 0; > > +} > > diff --git a/liblttng-ust-baddr/ust_baddr_statedump.c > > b/liblttng-ust-baddr/ust_baddr_statedump.c > > new file mode 100644 > > index 0000000..75f74ca > > --- /dev/null > > +++ b/liblttng-ust-baddr/ust_baddr_statedump.c > > @@ -0,0 +1,21 @@ > > +/* > > + * Copyright (C) 2013 Paul Woegerer <[email protected]> > > + * > > + * This library is free software; you can redistribute it and/or > > + * modify it under the terms of the GNU Lesser General Public > > + * License as published by the Free Software Foundation; either > > + * version 2.1 of the License, or (at your option) any later version. > > + * > > + * This library is distributed in the hope that it will be useful, > > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > > + * Lesser General Public License for more details. > > + * > > + * You should have received a copy of the GNU Lesser General Public > > + * License along with this library; if not, write to the Free Software > > + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA > 02110-1301 > > USA > > + */ > > + > > +#define TRACEPOINT_CREATE_PROBES > > +#define TP_SESSION_CHECK > > +#include "ust_baddr_statedump.h" > > diff --git a/liblttng-ust-baddr/ust_baddr_statedump.h > > b/liblttng-ust-baddr/ust_baddr_statedump.h > > new file mode 100644 > > index 0000000..77a9af4 > > --- /dev/null > > +++ b/liblttng-ust-baddr/ust_baddr_statedump.h > > @@ -0,0 +1,60 @@ > > +#undef TRACEPOINT_PROVIDER > > +#define TRACEPOINT_PROVIDER ust_baddr_statedump > > + > > +#if !defined(_TRACEPOINT_UST_BADDR_STATEDUMP_H) || > > defined(TRACEPOINT_HEADER_MULTI_READ) > > +#define _TRACEPOINT_UST_BADDR_STATEDUMP_H > > + > > +#ifdef __cplusplus > > +extern "C" { > > +#endif > > + > > +/* > > + * Copyright (C) 2013 Paul Woegerer <[email protected]> > > + * > > + * Permission is hereby granted, free of charge, to any person > obtaining a > > copy > > + * of this software and associated documentation files (the > "Software"), to > > deal > > + * in the Software without restriction, including without > limitation the > > rights > > + * to use, copy, modify, merge, publish, distribute, sublicense, > and/or sell > > + * copies of the Software, and to permit persons to whom the > Software is > > + * furnished to do so, subject to the following conditions: > > + * > > + * The above copyright notice and this permission notice shall be > included > > in > > + * all copies or substantial portions of the Software. > > + * > > + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, > EXPRESS > > OR > > + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF > MERCHANTABILITY, > > + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO > EVENT SHALL > > THE > > + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR > OTHER > > + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, > ARISING > > FROM, > > + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER > DEALINGS IN > > THE > > + * SOFTWARE. > > + */ > > + > > +#include <stdint.h> > > +#include <unistd.h> > > +#include <lttng/ust-events.h> > > + > > +#define LTTNG_UST_BADDR_STATEDUMP_PROVIDER > > +#include <lttng/tracepoint.h> > > + > > +TRACEPOINT_EVENT(ust_baddr_statedump, soinfo, > > + TP_ARGS(struct lttng_session *, session, void *, > baddr, const char*, > > sopath, int64_t, size, int64_t, mtime), > > + TP_FIELDS( > > + ctf_integer_hex(void *, baddr, baddr) > > + ctf_string(sopath, sopath) > > + ctf_integer(int64_t, size, size) > > + ctf_integer(int64_t, mtime, mtime) > > + ) > > +) > > + > > +#endif /* _TRACEPOINT_UST_BADDR_STATEDUMP_H */ > > + > > +#undef TRACEPOINT_INCLUDE > > +#define TRACEPOINT_INCLUDE "./ust_baddr_statedump.h" > > + > > +/* This part must be outside ifdef protection */ > > +#include <lttng/tracepoint-event.h> > > + > > +#ifdef __cplusplus > > +} > > +#endif > > diff --git a/liblttng-ust/lttng-events.c b/liblttng-ust/lttng-events.c > > index 26601a6..21e3639 100644 > > --- a/liblttng-ust/lttng-events.c > > +++ b/liblttng-ust/lttng-events.c > > @@ -293,6 +293,8 @@ int lttng_session_enable(struct lttng_session > *session) > > /* Set atomically the state to "active" */ > > CMM_ACCESS_ONCE(session->active) = 1; > > CMM_ACCESS_ONCE(session->been_active) = 1; > > + > > + lttng_ust_sockinfo_session_enabled(session->owner, > session); > > end: > > return ret; > > } > > diff --git a/liblttng-ust/lttng-tracer-core.h > > b/liblttng-ust/lttng-tracer-core.h > > index f643a7e..e7f549e 100644 > > --- a/liblttng-ust/lttng-tracer-core.h > > +++ b/liblttng-ust/lttng-tracer-core.h > > @@ -45,4 +45,7 @@ const char *lttng_ust_obj_get_name(int id); > > > > int lttng_get_notify_socket(void *owner); > > > > +void lttng_ust_sockinfo_session_enabled(void *owner, > > + struct lttng_session > *session_enabled); > > + > > #endif /* _LTTNG_TRACER_CORE_H */ > > diff --git a/liblttng-ust/lttng-ust-comm.c > b/liblttng-ust/lttng-ust-comm.c > > index a6e4ba3..6ef3006 100644 > > --- a/liblttng-ust/lttng-ust-comm.c > > +++ b/liblttng-ust/lttng-ust-comm.c > > @@ -34,6 +34,7 @@ > > #include <time.h> > > #include <assert.h> > > #include <signal.h> > > +#include <dlfcn.h> > > #include <urcu/uatomic.h> > > #include <urcu/futex.h> > > #include <urcu/compiler.h> > > @@ -106,6 +107,7 @@ struct sock_info { > > > > char wait_shm_path[PATH_MAX]; > > char *wait_shm_mmap; > > + struct lttng_session *session_enabled; > > }; > > > > /* Socket from app (connect) to session daemon (listen) for > communication */ > > @@ -122,6 +124,8 @@ struct sock_info global_apps = { > > .notify_socket = -1, > > > > .wait_shm_path = "/" LTTNG_UST_WAIT_FILENAME, > > + > > + .session_enabled = NULL, > > }; > > > > /* TODO: allow global_apps_sock_path override */ > > @@ -135,6 +139,8 @@ struct sock_info local_apps = { > > > > .socket = -1, > > .notify_socket = -1, > > + > > + .session_enabled = NULL, > > }; > > > > static int wait_poll_fallback; > > @@ -176,6 +182,7 @@ static const char *cmd_name_mapping[] = { > > > > static const char *str_timeout; > > static int got_timeout_env; > > +static void *ust_baddr_handle; > > > > extern void lttng_ring_buffer_client_overwrite_init(void); > > extern void lttng_ring_buffer_client_overwrite_rt_init(void); > > @@ -235,6 +242,39 @@ void print_cmd(int cmd, int handle) > > } > > > > static > > +void *lttng_ust_baddr_handle(void) > > +{ > > + if (!ust_baddr_handle) { > > + ust_baddr_handle = dlopen( > > + > "liblttng-ust-baddr.so.0", RTLD_NOW | RTLD_GLOBAL); > > + if (ust_baddr_handle == NULL) > > + ERR("%s", > dlerror()); > > + } > > + return ust_baddr_handle; > > +} > > + > > +static > > +int lttng_ust_baddr_statedump(struct lttng_session *session) > > +{ > > + static > > + int (*lttng_ust_baddr_init_fn)(struct > lttng_session *); > > + > > + if (!lttng_ust_baddr_init_fn) { > > + void *baddr_handle = > lttng_ust_baddr_handle(); > > + if (baddr_handle) { > > + > lttng_ust_baddr_init_fn = dlsym(baddr_handle, > > + > "lttng_ust_baddr_statedump"); > > + if > (lttng_ust_baddr_init_fn == NULL) > > + > ERR("%s", dlerror()); > > + } > > + if (!lttng_ust_baddr_init_fn) > > + return -1; > > + } > > + > > + return lttng_ust_baddr_init_fn(session); > > +} > > + > > +static > > int setup_local_apps(void) > > { > > const char *home_dir; > > @@ -1143,6 +1183,13 @@ restart: > > ret = > handle_message(sock_info, sock, &lum); > > if (ret) { > > > ERR("Error handling message for %s socket", sock_info->name); > > + } else { > > + > struct lttng_session *session = > > + > sock_info->session_enabled; > > + > if (session) { > > + > sock_info->session_enabled = NULL; > > + > lttng_ust_baddr_statedump(session); > > + } > > } > > continue; > > default: > > @@ -1379,6 +1426,12 @@ void __attribute__((destructor)) > lttng_ust_exit(void) > > * cleanup the threads if there are stalled in a > syscall. > > */ > > lttng_ust_cleanup(1); > > + > > + if (ust_baddr_handle) { > > + int ret = dlclose(ust_baddr_handle); > > + if (ret) > > + ERR("%s", > dlerror()); > > + } > > } > > > > /* > > @@ -1456,3 +1509,10 @@ void ust_after_fork_child(sigset_t > *restore_sigset) > > ust_after_fork_common(restore_sigset); > > lttng_ust_init(); > > } > > + > > +void lttng_ust_sockinfo_session_enabled(void *owner, > > + struct lttng_session > *session_enabled) > > +{ > > + struct sock_info *sock_info = owner; > > + sock_info->session_enabled = session_enabled; > > +} > > -- > > 1.8.4.2 > > > > > > -- > Mathieu Desnoyers > EfficiOS Inc._ > __http://www.efficios.com_ <http://www.efficios.com/> > > _______________________________________________ > lttng-dev mailing list > [email protected]_ > __http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev_ > > > > > > -- > Mathieu Desnoyers > EfficiOS Inc. > http://www.efficios.com <http://www.efficios.com/> -- Paul Woegerer, SW Development Engineer Sourcery Analyzer <http://go.mentor.com/sourceryanalyzer> Mentor Graphics, Embedded Software Division _______________________________________________ lttng-dev mailing list [email protected] http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
