* [RFC PATCH 0/2] Identify UST threads by changing thread names @ 2016-04-21 20:50 Raphaël Beamonte 0 siblings, 0 replies; 9+ messages in thread From: Raphaël Beamonte @ 2016-04-21 20:50 UTC (permalink / raw) To: lttng-dev; +Cc: Raphaël Beamonte Hi, This is an RFC patch for comments and ideas about how this should be done. In recent work I've been doing, I found out that some UST- instrumented userspace process was preempting itself. Looking further, it was not the same TID, but the same process name. These processes were LTTng-UST listener threads, but were not identified as so. Adding a simple symbol, such as "-ust" or "-lttng" at the end of the process name would help to identify such process directly in the generated trace. You'll find below two different implementations with their pros and cons, for which the "-ust" symbol was choosen: 1/ An implementation using prctl It works properly on Linux, but I didn't find a way to make it work under FreeBSD, hence the empty function in FreeBSD case (keeping the situation as it is now). Raphaël Beamonte (1): Add -ust to the name of UST threads of the application liblttng-ust/compat.h | 22 ++++++++++++++++++++++ liblttng-ust/lttng-ust-comm.c | 2 ++ 2 files changed, 24 insertions(+) 2/ An implementation using pthread It works on both Linux and FreeBSD, but requires to add a link to the pthread library in liblttng-ust Makefile.am. Also, this approach relies on the presence of the pthread_setname_np function, which was included in glibc 2.12, meaning it will not work with older versions (but this should not be a problem?) Raphaël Beamonte (1): Add -ust to the name of UST threads of the application liblttng-ust/Makefile.am | 1 + liblttng-ust/compat.h | 35 +++++++++++++++++++++++++++++++++++ liblttng-ust/lttng-ust-comm.c | 2 ++ 3 files changed, 38 insertions(+) I'll wait for your comments and ideas on that subject. Thanks, Raphaël -- 2.1.4 _______________________________________________ lttng-dev mailing list lttng-dev@lists.lttng.org https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev ^ permalink raw reply [flat|nested] 9+ messages in thread
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* Re: [RFC PATCH 0/2] Identify UST threads by changing thread names [not found] <cover.1461269886.git.raphael.beamonte@gmail.com> @ 2016-06-01 15:04 ` Raphaël Beamonte [not found] ` <CAE_Gge2jacOMKQaPdp_dXf3NP+yJTS+jWgJQ-SUnv1-B6WgcGw@mail.gmail.com> 1 sibling, 0 replies; 9+ messages in thread From: Raphaël Beamonte @ 2016-06-01 15:04 UTC (permalink / raw) To: lttng-dev Hi, I did not get any feedback about this, any thoughts ? Thanks, Raphaël 2016-04-21 16:50 GMT-04:00 Raphaël Beamonte <raphael.beamonte@gmail.com>: > Hi, > > This is an RFC patch for comments and ideas about how this should be > done. In recent work I've been doing, I found out that some UST- > instrumented userspace process was preempting itself. Looking further, > it was not the same TID, but the same process name. These processes > were LTTng-UST listener threads, but were not identified as so. > Adding a simple symbol, such as "-ust" or "-lttng" at the end of the > process name would help to identify such process directly in the > generated trace. > > You'll find below two different implementations with their pros > and cons, for which the "-ust" symbol was choosen: > > > 1/ An implementation using prctl > It works properly on Linux, but I didn't find a way to make > it work under FreeBSD, hence the empty function in FreeBSD > case (keeping the situation as it is now). > > Raphaël Beamonte (1): > Add -ust to the name of UST threads of the application > > liblttng-ust/compat.h | 22 ++++++++++++++++++++++ > liblttng-ust/lttng-ust-comm.c | 2 ++ > 2 files changed, 24 insertions(+) > > > > 2/ An implementation using pthread > It works on both Linux and FreeBSD, but requires to add a > link to the pthread library in liblttng-ust Makefile.am. > Also, this approach relies on the presence of the > pthread_setname_np function, which was included in glibc > 2.12, meaning it will not work with older versions (but > this should not be a problem?) > > Raphaël Beamonte (1): > Add -ust to the name of UST threads of the application > > liblttng-ust/Makefile.am | 1 + > liblttng-ust/compat.h | 35 +++++++++++++++++++++++++++++++++++ > liblttng-ust/lttng-ust-comm.c | 2 ++ > 3 files changed, 38 insertions(+) > > > > I'll wait for your comments and ideas on that subject. > > Thanks, > Raphaël > > > -- > 2.1.4 > _______________________________________________ lttng-dev mailing list lttng-dev@lists.lttng.org https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev ^ permalink raw reply [flat|nested] 9+ messages in thread
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* Re: [RFC PATCH 0/2] Identify UST threads by changing thread names [not found] ` <CAE_Gge2jacOMKQaPdp_dXf3NP+yJTS+jWgJQ-SUnv1-B6WgcGw@mail.gmail.com> @ 2016-06-03 6:10 ` Jérémie Galarneau [not found] ` <CA+jJMxvmHRYYtHWYjumXrS1BrBCih3WJnRA5yGFBXTw7jL3HiA@mail.gmail.com> 1 sibling, 0 replies; 9+ messages in thread From: Jérémie Galarneau @ 2016-06-03 6:10 UTC (permalink / raw) To: Raphaël Beamonte; +Cc: lttng-dev Hi Raphaël, Adding Mathieu in CC. Please make sure you CC the maintainers when submitting a patch. Regards, Jérémie On Wed, Jun 1, 2016 at 11:04 AM, Raphaël Beamonte <raphael.beamonte@gmail.com> wrote: > Hi, > > I did not get any feedback about this, any thoughts ? > > Thanks, > Raphaël > > 2016-04-21 16:50 GMT-04:00 Raphaël Beamonte <raphael.beamonte@gmail.com>: >> Hi, >> >> This is an RFC patch for comments and ideas about how this should be >> done. In recent work I've been doing, I found out that some UST- >> instrumented userspace process was preempting itself. Looking further, >> it was not the same TID, but the same process name. These processes >> were LTTng-UST listener threads, but were not identified as so. >> Adding a simple symbol, such as "-ust" or "-lttng" at the end of the >> process name would help to identify such process directly in the >> generated trace. >> >> You'll find below two different implementations with their pros >> and cons, for which the "-ust" symbol was choosen: >> >> >> 1/ An implementation using prctl >> It works properly on Linux, but I didn't find a way to make >> it work under FreeBSD, hence the empty function in FreeBSD >> case (keeping the situation as it is now). >> >> Raphaël Beamonte (1): >> Add -ust to the name of UST threads of the application >> >> liblttng-ust/compat.h | 22 ++++++++++++++++++++++ >> liblttng-ust/lttng-ust-comm.c | 2 ++ >> 2 files changed, 24 insertions(+) >> >> >> >> 2/ An implementation using pthread >> It works on both Linux and FreeBSD, but requires to add a >> link to the pthread library in liblttng-ust Makefile.am. >> Also, this approach relies on the presence of the >> pthread_setname_np function, which was included in glibc >> 2.12, meaning it will not work with older versions (but >> this should not be a problem?) >> >> Raphaël Beamonte (1): >> Add -ust to the name of UST threads of the application >> >> liblttng-ust/Makefile.am | 1 + >> liblttng-ust/compat.h | 35 +++++++++++++++++++++++++++++++++++ >> liblttng-ust/lttng-ust-comm.c | 2 ++ >> 3 files changed, 38 insertions(+) >> >> >> >> I'll wait for your comments and ideas on that subject. >> >> Thanks, >> Raphaël >> >> >> -- >> 2.1.4 >> > _______________________________________________ > lttng-dev mailing list > lttng-dev@lists.lttng.org > https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev -- Jérémie Galarneau EfficiOS Inc. http://www.efficios.com _______________________________________________ lttng-dev mailing list lttng-dev@lists.lttng.org https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev ^ permalink raw reply [flat|nested] 9+ messages in thread
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* Re: [RFC PATCH 0/2] Identify UST threads by changing thread names [not found] ` <CA+jJMxvmHRYYtHWYjumXrS1BrBCih3WJnRA5yGFBXTw7jL3HiA@mail.gmail.com> @ 2016-06-03 6:11 ` Jérémie Galarneau [not found] ` <CA+jJMxs9yNOeeqtYBfGTz1ADOqqiVO=XZd-7qm48BS8dzVo-iw@mail.gmail.com> 1 sibling, 0 replies; 9+ messages in thread From: Jérémie Galarneau @ 2016-06-03 6:11 UTC (permalink / raw) To: Raphaël Beamonte; +Cc: lttng-dev And, of course, I forget to add Mathieu in CC... Coffee time! Jérémie On Fri, Jun 3, 2016 at 2:10 AM, Jérémie Galarneau <jeremie.galarneau@efficios.com> wrote: > Hi Raphaël, > > Adding Mathieu in CC. Please make sure you CC the maintainers when > submitting a patch. > > Regards, > Jérémie > > On Wed, Jun 1, 2016 at 11:04 AM, Raphaël Beamonte > <raphael.beamonte@gmail.com> wrote: >> Hi, >> >> I did not get any feedback about this, any thoughts ? >> >> Thanks, >> Raphaël >> >> 2016-04-21 16:50 GMT-04:00 Raphaël Beamonte <raphael.beamonte@gmail.com>: >>> Hi, >>> >>> This is an RFC patch for comments and ideas about how this should be >>> done. In recent work I've been doing, I found out that some UST- >>> instrumented userspace process was preempting itself. Looking further, >>> it was not the same TID, but the same process name. These processes >>> were LTTng-UST listener threads, but were not identified as so. >>> Adding a simple symbol, such as "-ust" or "-lttng" at the end of the >>> process name would help to identify such process directly in the >>> generated trace. >>> >>> You'll find below two different implementations with their pros >>> and cons, for which the "-ust" symbol was choosen: >>> >>> >>> 1/ An implementation using prctl >>> It works properly on Linux, but I didn't find a way to make >>> it work under FreeBSD, hence the empty function in FreeBSD >>> case (keeping the situation as it is now). >>> >>> Raphaël Beamonte (1): >>> Add -ust to the name of UST threads of the application >>> >>> liblttng-ust/compat.h | 22 ++++++++++++++++++++++ >>> liblttng-ust/lttng-ust-comm.c | 2 ++ >>> 2 files changed, 24 insertions(+) >>> >>> >>> >>> 2/ An implementation using pthread >>> It works on both Linux and FreeBSD, but requires to add a >>> link to the pthread library in liblttng-ust Makefile.am. >>> Also, this approach relies on the presence of the >>> pthread_setname_np function, which was included in glibc >>> 2.12, meaning it will not work with older versions (but >>> this should not be a problem?) >>> >>> Raphaël Beamonte (1): >>> Add -ust to the name of UST threads of the application >>> >>> liblttng-ust/Makefile.am | 1 + >>> liblttng-ust/compat.h | 35 +++++++++++++++++++++++++++++++++++ >>> liblttng-ust/lttng-ust-comm.c | 2 ++ >>> 3 files changed, 38 insertions(+) >>> >>> >>> >>> I'll wait for your comments and ideas on that subject. >>> >>> Thanks, >>> Raphaël >>> >>> >>> -- >>> 2.1.4 >>> >> _______________________________________________ >> lttng-dev mailing list >> lttng-dev@lists.lttng.org >> https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev > > > > -- > Jérémie Galarneau > EfficiOS Inc. > http://www.efficios.com -- Jérémie Galarneau EfficiOS Inc. http://www.efficios.com _______________________________________________ lttng-dev mailing list lttng-dev@lists.lttng.org https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev ^ permalink raw reply [flat|nested] 9+ messages in thread
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* Re: [RFC PATCH 0/2] Identify UST threads by changing thread names [not found] ` <CA+jJMxs9yNOeeqtYBfGTz1ADOqqiVO=XZd-7qm48BS8dzVo-iw@mail.gmail.com> @ 2016-06-03 6:18 ` Mathieu Desnoyers [not found] ` <1192105907.26502.1464934699922.JavaMail.zimbra@efficios.com> 1 sibling, 0 replies; 9+ messages in thread From: Mathieu Desnoyers @ 2016-06-03 6:18 UTC (permalink / raw) To: Jeremie Galarneau; +Cc: Raphaël Beamonte, lttng-dev ----- On Jun 3, 2016, at 8:11 AM, Jeremie Galarneau jeremie.galarneau@efficios.com wrote: > And, of course, I forget to add Mathieu in CC... Coffee time! > > Jérémie > > On Fri, Jun 3, 2016 at 2:10 AM, Jérémie Galarneau > <jeremie.galarneau@efficios.com> wrote: >> Hi Raphaël, >> >> Adding Mathieu in CC. Please make sure you CC the maintainers when >> submitting a patch. >> >> Regards, >> Jérémie >> >> On Wed, Jun 1, 2016 at 11:04 AM, Raphaël Beamonte >> <raphael.beamonte@gmail.com> wrote: >>> Hi, >>> >>> I did not get any feedback about this, any thoughts ? >>> >>> Thanks, >>> Raphaël >>> >>> 2016-04-21 16:50 GMT-04:00 Raphaël Beamonte <raphael.beamonte@gmail.com>: >>>> Hi, >>>> >>>> This is an RFC patch for comments and ideas about how this should be >>>> done. In recent work I've been doing, I found out that some UST- >>>> instrumented userspace process was preempting itself. Looking further, >>>> it was not the same TID, but the same process name. These processes >>>> were LTTng-UST listener threads, but were not identified as so. >>>> Adding a simple symbol, such as "-ust" or "-lttng" at the end of the >>>> process name would help to identify such process directly in the >>>> generated trace. >>>> >>>> You'll find below two different implementations with their pros >>>> and cons, for which the "-ust" symbol was choosen: >>>> >>>> >>>> 1/ An implementation using prctl >>>> It works properly on Linux, but I didn't find a way to make >>>> it work under FreeBSD, hence the empty function in FreeBSD >>>> case (keeping the situation as it is now). >>>> >>>> Raphaël Beamonte (1): >>>> Add -ust to the name of UST threads of the application >>>> >>>> liblttng-ust/compat.h | 22 ++++++++++++++++++++++ >>>> liblttng-ust/lttng-ust-comm.c | 2 ++ >>>> 2 files changed, 24 insertions(+) >>>> >>>> >>>> >>>> 2/ An implementation using pthread >>>> It works on both Linux and FreeBSD, but requires to add a >>>> link to the pthread library in liblttng-ust Makefile.am. >>>> Also, this approach relies on the presence of the >>>> pthread_setname_np function, which was included in glibc >>>> 2.12, meaning it will not work with older versions (but >>>> this should not be a problem?) lttng-ust already uses libc for mutexes and other. So I don't see why you have to _add_ any explicit dependency there. About the glibc version, we should use autotools to detect the features supported by the system libc, and pass a config define to the source code, so we can use the glibc pthread_setname_np if available, else we keep the current behavior. Thoughts ? Thanks, Mathieu >>>> >>>> Raphaël Beamonte (1): >>>> Add -ust to the name of UST threads of the application >>>> >>>> liblttng-ust/Makefile.am | 1 + >>>> liblttng-ust/compat.h | 35 +++++++++++++++++++++++++++++++++++ >>>> liblttng-ust/lttng-ust-comm.c | 2 ++ >>>> 3 files changed, 38 insertions(+) >>>> >>>> >>>> >>>> I'll wait for your comments and ideas on that subject. >>>> >>>> Thanks, >>>> Raphaël >>>> >>>> >>>> -- >>>> 2.1.4 >>>> >>> _______________________________________________ >>> lttng-dev mailing list >>> lttng-dev@lists.lttng.org >>> https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev >> >> >> >> -- >> Jérémie Galarneau >> EfficiOS Inc. >> http://www.efficios.com > > > > -- > Jérémie Galarneau > EfficiOS Inc. > http://www.efficios.com -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com _______________________________________________ lttng-dev mailing list lttng-dev@lists.lttng.org https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev ^ permalink raw reply [flat|nested] 9+ messages in thread
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* Re: [RFC PATCH 0/2] Identify UST threads by changing thread names [not found] ` <1192105907.26502.1464934699922.JavaMail.zimbra@efficios.com> @ 2016-06-03 6:24 ` Mathieu Desnoyers [not found] ` <293416701.26545.1464935065348.JavaMail.zimbra@efficios.com> 1 sibling, 0 replies; 9+ messages in thread From: Mathieu Desnoyers @ 2016-06-03 6:24 UTC (permalink / raw) To: Jeremie Galarneau; +Cc: Raphaël Beamonte, lttng-dev ----- On Jun 3, 2016, at 8:18 AM, Mathieu Desnoyers mathieu.desnoyers@efficios.com wrote: > ----- On Jun 3, 2016, at 8:11 AM, Jeremie Galarneau > jeremie.galarneau@efficios.com wrote: > >> And, of course, I forget to add Mathieu in CC... Coffee time! >> >> Jérémie >> >> On Fri, Jun 3, 2016 at 2:10 AM, Jérémie Galarneau >> <jeremie.galarneau@efficios.com> wrote: >>> Hi Raphaël, >>> >>> Adding Mathieu in CC. Please make sure you CC the maintainers when >>> submitting a patch. >>> >>> Regards, >>> Jérémie >>> >>> On Wed, Jun 1, 2016 at 11:04 AM, Raphaël Beamonte >>> <raphael.beamonte@gmail.com> wrote: >>>> Hi, >>>> >>>> I did not get any feedback about this, any thoughts ? >>>> >>>> Thanks, >>>> Raphaël >>>> >>>> 2016-04-21 16:50 GMT-04:00 Raphaël Beamonte <raphael.beamonte@gmail.com>: >>>>> Hi, >>>>> >>>>> This is an RFC patch for comments and ideas about how this should be >>>>> done. In recent work I've been doing, I found out that some UST- >>>>> instrumented userspace process was preempting itself. Looking further, >>>>> it was not the same TID, but the same process name. These processes >>>>> were LTTng-UST listener threads, but were not identified as so. >>>>> Adding a simple symbol, such as "-ust" or "-lttng" at the end of the >>>>> process name would help to identify such process directly in the >>>>> generated trace. >>>>> >>>>> You'll find below two different implementations with their pros >>>>> and cons, for which the "-ust" symbol was choosen: >>>>> >>>>> >>>>> 1/ An implementation using prctl >>>>> It works properly on Linux, but I didn't find a way to make >>>>> it work under FreeBSD, hence the empty function in FreeBSD >>>>> case (keeping the situation as it is now). >>>>> >>>>> Raphaël Beamonte (1): >>>>> Add -ust to the name of UST threads of the application >>>>> >>>>> liblttng-ust/compat.h | 22 ++++++++++++++++++++++ >>>>> liblttng-ust/lttng-ust-comm.c | 2 ++ >>>>> 2 files changed, 24 insertions(+) >>>>> >>>>> >>>>> >>>>> 2/ An implementation using pthread >>>>> It works on both Linux and FreeBSD, but requires to add a >>>>> link to the pthread library in liblttng-ust Makefile.am. >>>>> Also, this approach relies on the presence of the >>>>> pthread_setname_np function, which was included in glibc >>>>> 2.12, meaning it will not work with older versions (but >>>>> this should not be a problem?) > > lttng-ust already uses libc for mutexes and other. So I don't see why > you have to _add_ any explicit dependency there. and we already explicitly use pthread (pthread_create). Thanks, Mathieu > > About the glibc version, we should use autotools to detect the > features supported by the system libc, and pass a config define > to the source code, so we can use the glibc pthread_setname_np > if available, else we keep the current behavior. > > Thoughts ? > > Thanks, > > Mathieu > >>>>> >>>>> Raphaël Beamonte (1): >>>>> Add -ust to the name of UST threads of the application >>>>> >>>>> liblttng-ust/Makefile.am | 1 + >>>>> liblttng-ust/compat.h | 35 +++++++++++++++++++++++++++++++++++ >>>>> liblttng-ust/lttng-ust-comm.c | 2 ++ >>>>> 3 files changed, 38 insertions(+) >>>>> >>>>> >>>>> >>>>> I'll wait for your comments and ideas on that subject. >>>>> >>>>> Thanks, >>>>> Raphaël >>>>> >>>>> >>>>> -- >>>>> 2.1.4 >>>>> >>>> _______________________________________________ >>>> lttng-dev mailing list >>>> lttng-dev@lists.lttng.org >>>> https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev >>> >>> >>> >>> -- >>> Jérémie Galarneau >>> EfficiOS Inc. >>> http://www.efficios.com >> >> >> >> -- >> Jérémie Galarneau >> EfficiOS Inc. >> http://www.efficios.com > > -- > Mathieu Desnoyers > EfficiOS Inc. > http://www.efficios.com > _______________________________________________ > lttng-dev mailing list > lttng-dev@lists.lttng.org > https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com _______________________________________________ lttng-dev mailing list lttng-dev@lists.lttng.org https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev ^ permalink raw reply [flat|nested] 9+ messages in thread
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* Re: [RFC PATCH 0/2] Identify UST threads by changing thread names [not found] ` <293416701.26545.1464935065348.JavaMail.zimbra@efficios.com> @ 2016-06-03 14:12 ` Raphaël Beamonte [not found] ` <CAE_Gge2032JkDubp=vpaqNzoQre7MfvQC4UGm-wXPmux-Fwh6g@mail.gmail.com> 1 sibling, 0 replies; 9+ messages in thread From: Raphaël Beamonte @ 2016-06-03 14:12 UTC (permalink / raw) To: Mathieu Desnoyers; +Cc: lttng-dev Hi! Thanks for all of your comments, I appreciate it! Thanks Jeremie for adding Mathieu in Cc, forgot to do it... Will remember next time! :) 2016-06-02 9:22 GMT-04:00 Sebastien Boisvert <sboisvert@gydle.com>: > Do you know if the name of these listener threads can be set in their constructor, directly > when they are brought into this world ? pthread_create does not allow to specify a name when creating the new thread, as far as I know! That's why the 'lttng_ust_setustprocname()' function is called first thing in the ust_listener_thread function. > Perhaps the availability of pthread_setname_np and/or pthread_set_name_np (you have both names > in your patch 2) should be ascertained in another venue, such as the configure.ac -- where it belongs. True! 2016-06-03 2:24 GMT-04:00 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>: > ----- On Jun 3, 2016, at 8:18 AM, Mathieu Desnoyers mathieu.desnoyers@efficios.com wrote: >> lttng-ust already uses libc for mutexes and other. So I don't see why >> you have to _add_ any explicit dependency there. > > and we already explicitly use pthread (pthread_create). You're right, pthread is already used. However, when compiling the code without adding the pthread dependency, I get the following warning: In file included from lttng-tracer.h:30:0, from lttng-ust-abi.c:50: compat.h: In function ‘lttng_ust_setustprocname’: compat.h:52:2: warning: implicit declaration of function ‘pthread_setname_np’ [-Wimplicit-function-declaration] pthread_setname_np(pthread_self(), name); ^ CC lttng-context-procname.lo In file included from lttng-context-procname.c:28:0: compat.h: In function ‘lttng_ust_setustprocname’: compat.h:52:2: warning: implicit declaration of function ‘pthread_setname_np’ [-Wimplicit-function-declaration] pthread_setname_np(pthread_self(), name); ^ It seems to be because pthread is not specified as dependency for liblttng-ust-tracepoint in liblttng-ust/Makefile.am. However, perhaps that pthread dependency should be added elsewhere? >> About the glibc version, we should use autotools to detect the >> features supported by the system libc, and pass a config define >> to the source code, so we can use the glibc pthread_setname_np >> if available, else we keep the current behavior. That's a good idea, will do! I'll update and rebase the patch following your comments. If you have any other insight about the pthread dependency, I'm all ears! Thanks, Raphaël _______________________________________________ lttng-dev mailing list lttng-dev@lists.lttng.org https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev ^ permalink raw reply [flat|nested] 9+ messages in thread
[parent not found: <CAE_Gge2032JkDubp=vpaqNzoQre7MfvQC4UGm-wXPmux-Fwh6g@mail.gmail.com>]
* Re: [RFC PATCH 0/2] Identify UST threads by changing thread names [not found] ` <CAE_Gge2032JkDubp=vpaqNzoQre7MfvQC4UGm-wXPmux-Fwh6g@mail.gmail.com> @ 2016-06-03 15:38 ` Mathieu Desnoyers 0 siblings, 0 replies; 9+ messages in thread From: Mathieu Desnoyers @ 2016-06-03 15:38 UTC (permalink / raw) To: Raphaël Beamonte; +Cc: lttng-dev ----- On Jun 3, 2016, at 4:12 PM, Raphaël Beamonte raphael.beamonte@gmail.com wrote: > Hi! > > Thanks for all of your comments, I appreciate it! > Thanks Jeremie for adding Mathieu in Cc, forgot to do it... Will > remember next time! :) > > 2016-06-02 9:22 GMT-04:00 Sebastien Boisvert <sboisvert@gydle.com>: >> Do you know if the name of these listener threads can be set in their >> constructor, directly >> when they are brought into this world ? > > pthread_create does not allow to specify a name when creating the new > thread, as far as I know! That's why the 'lttng_ust_setustprocname()' > function is called first thing in the ust_listener_thread function. > >> Perhaps the availability of pthread_setname_np and/or pthread_set_name_np (you >> have both names >> in your patch 2) should be ascertained in another venue, such as the >> configure.ac -- where it belongs. > > True! > > 2016-06-03 2:24 GMT-04:00 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>: >> ----- On Jun 3, 2016, at 8:18 AM, Mathieu Desnoyers >> mathieu.desnoyers@efficios.com wrote: >>> lttng-ust already uses libc for mutexes and other. So I don't see why >>> you have to _add_ any explicit dependency there. >> >> and we already explicitly use pthread (pthread_create). > > You're right, pthread is already used. However, when compiling the > code without adding the pthread dependency, I get the following > warning: > > In file included from lttng-tracer.h:30:0, > from lttng-ust-abi.c:50: > compat.h: In function ‘lttng_ust_setustprocname’: > compat.h:52:2: warning: implicit declaration of function > ‘pthread_setname_np’ [-Wimplicit-function-declaration] > pthread_setname_np(pthread_self(), name); > ^ > CC lttng-context-procname.lo > In file included from lttng-context-procname.c:28:0: > compat.h: In function ‘lttng_ust_setustprocname’: > compat.h:52:2: warning: implicit declaration of function > ‘pthread_setname_np’ [-Wimplicit-function-declaration] > pthread_setname_np(pthread_self(), name); > ^ > > It seems to be because pthread is not specified as dependency for > liblttng-ust-tracepoint in liblttng-ust/Makefile.am. However, perhaps > that pthread dependency should be added elsewhere? Seems fair. Thanks, Mathieu > >>> About the glibc version, we should use autotools to detect the >>> features supported by the system libc, and pass a config define >>> to the source code, so we can use the glibc pthread_setname_np >>> if available, else we keep the current behavior. > > That's a good idea, will do! > > I'll update and rebase the patch following your comments. > If you have any other insight about the pthread dependency, I'm all ears! > > Thanks, > Raphaël -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com _______________________________________________ lttng-dev mailing list lttng-dev@lists.lttng.org https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev ^ permalink raw reply [flat|nested] 9+ messages in thread
[parent not found: <5750318D.3020709@gydle.com>]
* Re: [RFC PATCH 0/2] Identify UST threads by changing thread names [not found] <5750318D.3020709@gydle.com> @ 2016-06-02 13:22 ` Sebastien Boisvert 0 siblings, 0 replies; 9+ messages in thread From: Sebastien Boisvert @ 2016-06-02 13:22 UTC (permalink / raw) To: Raphaël Beamonte; +Cc: lttng-dev Hi Raphaël, > Hi, > > This is an RFC patch for comments and ideas about how this should be > done. In recent work I've been doing, I found out that some UST- > instrumented userspace process was preempting itself. Looking further, > it was not the same TID, but the same process name. These processes > were LTTng-UST listener threads, but were not identified as so. > Adding a simple symbol, such as "-ust" or "-lttng" at the end of the > process name would help to identify such process directly in the > generated trace. Do you know if the name of these listener threads can be set in their constructor, directly when they are brought into this world ? > > You'll find below two different implementations with their pros > and cons, for which the "-ust" symbol was choosen: > > > 1/ An implementation using prctl > It works properly on Linux, but I didn't find a way to make > it work under FreeBSD, hence the empty function in FreeBSD > case (keeping the situation as it is now). > > Raphaël Beamonte (1): > Add -ust to the name of UST threads of the application > > liblttng-ust/compat.h | 22 ++++++++++++++++++++++ > liblttng-ust/lttng-ust-comm.c | 2 ++ > 2 files changed, 24 insertions(+) > > I prefer this one. It is less complex, in my opinion. > > 2/ An implementation using pthread > It works on both Linux and FreeBSD, but requires to add a > link to the pthread library in liblttng-ust Makefile.am. > Also, this approach relies on the presence of the > pthread_setname_np function, which was included in glibc > 2.12, meaning it will not work with older versions (but > this should not be a problem?) > > Raphaël Beamonte (1): > Add -ust to the name of UST threads of the application > > liblttng-ust/Makefile.am | 1 + > liblttng-ust/compat.h | 35 +++++++++++++++++++++++++++++++++++ > liblttng-ust/lttng-ust-comm.c | 2 ++ > 3 files changed, 38 insertions(+) > Perhaps the availability of pthread_setname_np and/or pthread_set_name_np (you have both names in your patch 2) should be ascertained in another venue, such as the configure.ac -- where it belongs. > > > I'll wait for your comments and ideas on that subject. > > Thanks, > Raphaël > > _______________________________________________ lttng-dev mailing list lttng-dev@lists.lttng.org https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev ^ permalink raw reply [flat|nested] 9+ messages in thread
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2016-04-21 20:50 [RFC PATCH 0/2] Identify UST threads by changing thread names Raphaël Beamonte
[not found] <cover.1461269886.git.raphael.beamonte@gmail.com>
2016-06-01 15:04 ` Raphaël Beamonte
[not found] ` <CAE_Gge2jacOMKQaPdp_dXf3NP+yJTS+jWgJQ-SUnv1-B6WgcGw@mail.gmail.com>
2016-06-03 6:10 ` Jérémie Galarneau
[not found] ` <CA+jJMxvmHRYYtHWYjumXrS1BrBCih3WJnRA5yGFBXTw7jL3HiA@mail.gmail.com>
2016-06-03 6:11 ` Jérémie Galarneau
[not found] ` <CA+jJMxs9yNOeeqtYBfGTz1ADOqqiVO=XZd-7qm48BS8dzVo-iw@mail.gmail.com>
2016-06-03 6:18 ` Mathieu Desnoyers
[not found] ` <1192105907.26502.1464934699922.JavaMail.zimbra@efficios.com>
2016-06-03 6:24 ` Mathieu Desnoyers
[not found] ` <293416701.26545.1464935065348.JavaMail.zimbra@efficios.com>
2016-06-03 14:12 ` Raphaël Beamonte
[not found] ` <CAE_Gge2032JkDubp=vpaqNzoQre7MfvQC4UGm-wXPmux-Fwh6g@mail.gmail.com>
2016-06-03 15:38 ` Mathieu Desnoyers
[not found] <5750318D.3020709@gydle.com>
2016-06-02 13:22 ` Sebastien Boisvert
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