Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751585AbbK2PWn (ORCPT ); Sun, 29 Nov 2015 10:22:43 -0500 Received: from mail-pa0-f45.google.com ([209.85.220.45]:34809 "EHLO mail-pa0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751013AbbK2PWk (ORCPT ); Sun, 29 Nov 2015 10:22:40 -0500 Date: Mon, 30 Nov 2015 00:22:07 +0900 From: Namhyung Kim To: Tom Zanussi Cc: rostedt@goodmis.org, daniel.wagner@bmw-carit.de, masami.hiramatsu.pt@hitachi.com, josh@joshtriplett.org, andi@firstfloor.org, mathieu.desnoyers@efficios.com, peterz@infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 00/30] tracing: 'hist' triggers Message-ID: <20151129152207.GD16382@danjae.kornet> References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 17504 Lines: 351 On Mon, Nov 23, 2015 at 01:51:15PM -0600, Tom Zanussi wrote: > This is v12 of the 'hist triggers' patchset, incorporating suggestions > and fixing problems pointed out by Namhyung. Thanks for doing this work! This version looks good to me although I have a small nitpick in the 10/30. With that fixed, you can add my Reviewed-by: Namhyung Kim to this patchset. Thanks, Namhyung > > Changes from v11: > > - Added tracing_map_lookup(). > - Changed tracing_map_insert() to incorporate the hits/drops counter > updating. The changes allow clients to continue calling > tracing_map_insert() and update existing entries if desired, or > stop on the first drop, since the return value is still NULL in > that case. > - Changed the hist trigger code to continue calling > tracing_map_insert() rather than stopping on the first drop. The > idea is that there's no harm in continuing after the first drop - > if the user can't tolerate any drops, they'll still see a non-zero > drop count and can retry with a larger table, but if the user > doesn't care, the hit and drop counts are an accurate reflection > of how many events were tallied vs dropped. > - Added a new unreg_all() callback to event_command, and code to > call it when the trigger file is opened for truncate. Implemented > unreg_all() for hist triggers, which allows them to honor the > truncate flag while leaving existing triggers intact. This means > that '>>' should now be used for adding multiple hist triggers as > well as to clear/pause/cont an existing hist trigger. > - Included Namhyung's log2 patch. > - Fixed one of Masami's test cases which now requires using '>>' due > to the truncate changes. > - 'cont' and 'clear' no longer create a trigger if one doesn't exist. > - Rebased to latest trace/for-next. > - Various other smaller fixes and Documentation updates as noted by > Namhyung. > > Changes from v10: > > - Rebased to latest trace/for-next. > - Added Masami's ftrace/hist triggers kselftest patches. > - Added Masami's Tested-by: to the series. > > Changes from v9: > > v10 adds some major new features - 'named' hist triggers and support > for multiple hist triggers on a single event - basically all of the > features and suggestions suggested by Masami, except for one: I > decided after all not to implement the 'pause/continue/clear' commands > on the hist file. I've gotten so used to the habit of calling up the > previous trigger-setting command in the command history and simply > appending a 'pause/cont/clear' command to it (and later removing it by > prepending a '!') that making the user change the command doesn't seem > as naturally usable. Masami, if you disagree, let me know and I'll > reconsider it but at this point I'd rather not make that change. > > In addition, I think I've fixed all the other various smaller problems > mentioned in the previous review, please let me know if I missed any... > > - Added support for 'named' hist triggers > - Added support for multiple hist triggers on a single trace event > - Added documentation and examples for the above new features > - Streamlined the README to only include the essentials for hist triggers > - Fixed the 'hex' modifier for values, which was previously ignored > - Replaced the kmalloc of large arrays with a simple page-based scheme > - Fixed the tracing_map_insert() case where jhash returns 0 > - Fixed various other small problems noted along the way > > Changes from v8: > > Same as v8, but with the RFC patch [ftrace: Add function_hist tracer] > removed, and rebased to latest trace/for-next. > > Changes from v7: > > This version refactors the commits as suggested by Masami. There are > now more commits, but the result should be much more reviewable. The > ending code is the same as before, modulo a couple minor bug fixes I > discovered while refactoring and testing. > > I've also reviewed and fixed a number of shortcomings and errors in > the comments, and have added a new discussion of the tracing_map data > structures after Steve mentioned he found them confusing and/or > insufficiently documented. > > Also, I kept Namhyung's string patch [tracing: Support string type key > properly] as submitted, but added a follow-on patch that refactors it > and fixes a problem I found with it that enabled static string keys to > contain random chars and therefore incorrect map insertions. > > Changes from v6: > > This version adds a new 'sym-offset' modifier as requested by Masami. > I implemented it as a modifier rather than using the trace option as > suggested, in part because I wanted to keep it all self-contained and > it seemed more consistent to just add it alongside the 'sym' modifier. > Also, hist triggers arent't really a tracer and therefore don't > directly tie into the option update/callback mechanism so making use > of it isn't as simple as a normal tracer. > > I also changed the sort key specification to be stricter and signal an > error if the specified sort key wasn't found (rather than defaulting > to hitcount in those cases), also suggested by Masami. Thanks, > Masami, for your input! > > Also updated the Documentation and tracing/README to reflect the > changes. > > Changes from v5: > > This version adds support for compound keys, along with the related > ability to sort using primary and secondary keys. This was mentioned > in previous versions as the last important piece that remained > unimplemented, and is now implemented. (I didn't have time to get to > the couple of enhancements suggested by Masami, but I expect to be > able to add those later on top of these.) > > Because we now support compound keys and it's not immediately clear in > the output exactly which fields correspond to keys, the key(s), > compound or not, are now enclosed by curly braces. > > The Documentation and README have been updated to reflect the changes, > and several new examples have been added to illustrate how to use > compound keys. > > Also, the code was updated to work with the new ftrace_event_file, > etc, renaming in tracing/for-next. > > Changes from v4: > > This version addresses some problems and suggestions made by Daniel > Wagner - a lot of the code was reworked to get rid of the distinction > between keys and values, and as a result, both keys and values can be > used as sort keys. As suggested, it also allows 'val=' to be absent > in a trigger command - if no 'val' is specified, hitcount is assumed > and automatically used as the only val. > > The map code was also separated out into a separate file, > tracing_map.c, allowing it to be reused. It also adds a second tracer > called function_hist that actually does reuse the code, as an RFC > patch. > > Patch 01/10 [tracing: Update cond flag when enabling or disabling..] > is a fix for a problem noticed by Daniel and that fixes a problem in > existing trigger code and should be applied regardless of whether the > rest of the patchset is merged. > > As mentioned, patch 10/10 is an RFC patch implementing a new tracer > based on the function tracer code. It's a fun little tool and is > useful for a specific problem I'm working on (and is also a nice test > of the tracing_map code), but is an RFC because first, I'm not sure it > would really be of general interest and secondly, it's POC-level > quality and I'd need to spend more time fixing it up to make it > upstreamable, but I don't want to waste my time if not. > > There are a couple of important bits of functionality that were > present in v1 but not yet reimplemented in v5. > > The first is support for compound keys. Currently, maps can only be > keyed on a single event field, whereas in v1 they could be keyed on > multiple keys. With support for compound keys, you can create much > more interesting output, such as for example per-pid lists of > syscalls or read counts e.g.: > > # echo 'hist:keys=common_pid.execname,id.syscall:vals=hitcount' > \ > /sys/kernel/debug/tracing/events/raw_syscalls/sys_enter/trigger > > # cat /sys/kernel/debug/tracing/events/raw_syscalls/sys_enter/hist > > key: common_pid:bash[3112], id:sys_write vals: count:69 > key: common_pid:bash[3112], id:sys_rt_sigprocmask vals: count:218 > > key: common_pid:update-notifier[3164], id:sys_poll vals: count:37 > key: common_pid:update-notifier[3164], id:sys_recvfrom vals: count:118 > > key: common_pid:deja-dup-monito[3194], id:sys_sendto vals: count:1 > key: common_pid:deja-dup-monito[3194], id:sys_read vals: count:4 > key: common_pid:deja-dup-monito[3194], id:sys_poll vals: count:8 > key: common_pid:deja-dup-monito[3194], id:sys_recvmsg vals: count:8 > key: common_pid:deja-dup-monito[3194], id:sys_getegid vals: count:8 > > key: common_pid:emacs[3275], id:sys_fsync vals: count:1 > key: common_pid:emacs[3275], id:sys_open vals: count:1 > key: common_pid:emacs[3275], id:sys_symlink vals: count:2 > key: common_pid:emacs[3275], id:sys_poll vals: count:23 > key: common_pid:emacs[3275], id:sys_select vals: count:23 > key: common_pid:emacs[3275], id:unknown_syscall vals: count:34 > key: common_pid:emacs[3275], id:sys_ioctl vals: count:60 > key: common_pid:emacs[3275], id:sys_rt_sigprocmask vals: count:116 > > key: common_pid:cat[3323], id:sys_munmap vals: count:1 > key: common_pid:cat[3323], id:sys_fadvise64 vals: count:1 > > Related to that is support for sorting on multiple fields. Currently, > you can sort using only a primary key. Being able to sort on multiple > or at least a secondary key is indispensible for seeing trends when > displaying multiple values. > > Changes from v3: > > v4 fixes the race in tracing_map_insert() noted in v3, where > map.val.key could be checked even if map.val wasn't yet set. The > simple fix for that in tracing_map_insert() introduces the possibility > of duplicates in the map, which though rare, need to be accounted for > in the output. To address that, duplicate-merging code was added to > the map-printing code. > > It was also pointed out that it didn't seem correct to include > module.h, but the fix for that has deeper roots and is being addressed > by a separate patchset; for now we need to continue including > module.h, though prompted by that I did some other header include > cleanup. > > The functionality remains the same as v2, but this version no longer > tries to export and use bpf_maps, and more importantly removes the > associated GFP_NOTRACE/trace event hacks and kmem macros required to > work around the bpf_map implementation. > > The tracing_map functionality is instead built on top of a simple > lock-free map algorithm originated by Dr. Cliff Click (see references > in the code for more details), which though too restrictive to be > general-purpose in its current form, functions nicely as a > special-purpose tracing map. > > v3 also moves the hist triggers code into a separate file and puts it > all behind a new config option, CONFIG_HIST_TRIGGERS. It also merges > in the sorting code rather than keeping it as a separate patch. > > This patchset also includes a couple other new and related triggers, > enable_hist and disable_hist, very similar to the existing > enable_event/disable_event triggers used to automatically enable and > disable events based on a triggering condition, but in this case > allowing hist triggers to be enabled and disabled in the same way. > > - Added an insert check for val before checking the key associated with val > - Added code to merge possible duplicates in the map > > Changes from v2: > - reimplemented tracing_map, replacing bpf_map with nmi-safe/lock-free map > - removed GPF_NOTRACE, kmalloc/free macros and event hacks needed by bpf_maps > - moved hist triggers from trace_events_trigger.c to trace_events_hist.c > - added CONFIG_HIST_TRIGGERS config option > - consolidated sorting code with main patch > > Changes from v1: > - completely rewritten on top of tracing_map (renamed and exported bpf_map) > - added map clearing and client ops to tracing_map > - changed the name from 'hash' triggers to 'hist' triggers > - added new trigger 'pause' feature > - added new enable_hist and disable_hist triggers > - added usage for hist/enable_hist/disable hist to tracing/README > - moved examples into Documentation/trace/event.txt > - added ___GFP_NOTRACE, kmalloc/kfree macros, and conditional kmem tracepoints > > The following changes since commit e428abbbf616cd8fdd1162e4a624ad1d47b47544: > > tracing: #ifdef out uses of max trace when CONFIG_TRACER_MAX_TRACE is not set (2015-11-10 10:16:05 -0500) > > are available in the git repository at: > > git://git.yoctoproject.org/linux-yocto-contrib.git tzanussi/hist-triggers-v12 > http://git.yoctoproject.org/cgit/cgit.cgi/linux-yocto-contrib/log/?h=tzanussi/hist-triggers-v12 > > Masami Hiramatsu (2): > kselftests/ftrace : Add event trigger testcases > kselftests/ftrace: Add hist trigger testcases > > Namhyung Kim (2): > tracing: Support string type key properly > tracing: Add hist trigger 'log2' modifier > > Tom Zanussi (26): > tracing: Update cond flag when enabling or disabling a trigger > tracing: Make ftrace_event_field checking functions available > tracing: Make event trigger functions available > tracing: Add event record param to trigger_ops.func() > tracing: Add get_syscall_name() > tracing: Add a per-event-trigger 'paused' field > tracing: Add needs_rec flag to event triggers > tracing: Add an unreg_all() callback to trigger commands > tracing: Add lock-free tracing_map > tracing: Add 'hist' event trigger command > tracing: Add hist trigger support for multiple values ('vals=' param) > tracing: Add hist trigger support for compound keys > tracing: Add hist trigger support for user-defined sorting ('sort=' > param) > tracing: Add hist trigger support for pausing and continuing a trace > tracing: Add hist trigger support for clearing a trace > tracing: Add hist trigger 'hex' modifier for displaying numeric fields > tracing: Add hist trigger 'sym' and 'sym-offset' modifiers > tracing: Add hist trigger 'execname' modifier > tracing: Add hist trigger 'syscall' modifier > tracing: Add hist trigger support for stacktraces as keys > tracing: Remove restriction on string position in hist trigger keys > tracing: Add enable_hist/disable_hist triggers > tracing: Add 'hist' trigger Documentation > tracing: Add support for multiple hist triggers per event > tracing: Add support for named triggers > tracing: Add support for named hist triggers > > Documentation/trace/events.txt | 1555 ++++++++++++++++++ > include/linux/trace_events.h | 9 +- > kernel/trace/Kconfig | 27 + > kernel/trace/Makefile | 2 + > kernel/trace/trace.c | 57 + > kernel/trace/trace.h | 106 +- > kernel/trace/trace_events.c | 4 + > kernel/trace/trace_events_filter.c | 12 - > kernel/trace/trace_events_hist.c | 1731 ++++++++++++++++++++ > kernel/trace/trace_events_trigger.c | 309 +++- > kernel/trace/trace_syscalls.c | 11 + > kernel/trace/tracing_map.c | 1058 ++++++++++++ > kernel/trace/tracing_map.h | 282 ++++ > tools/testing/selftests/ftrace/test.d/functions | 9 + > .../ftrace/test.d/trigger/trigger-eventonoff.tc | 64 + > .../ftrace/test.d/trigger/trigger-filter.tc | 59 + > .../ftrace/test.d/trigger/trigger-hist-mod.tc | 65 + > .../ftrace/test.d/trigger/trigger-hist.tc | 83 + > .../ftrace/test.d/trigger/trigger-multihist.tc | 73 + > .../ftrace/test.d/trigger/trigger-snapshot.tc | 56 + > .../ftrace/test.d/trigger/trigger-stacktrace.tc | 53 + > .../ftrace/test.d/trigger/trigger-traceonoff.tc | 58 + > 22 files changed, 5596 insertions(+), 87 deletions(-) > create mode 100644 kernel/trace/trace_events_hist.c > create mode 100644 kernel/trace/tracing_map.c > create mode 100644 kernel/trace/tracing_map.h > create mode 100644 tools/testing/selftests/ftrace/test.d/trigger/trigger-eventonoff.tc > create mode 100644 tools/testing/selftests/ftrace/test.d/trigger/trigger-filter.tc > create mode 100644 tools/testing/selftests/ftrace/test.d/trigger/trigger-hist-mod.tc > create mode 100644 tools/testing/selftests/ftrace/test.d/trigger/trigger-hist.tc > create mode 100644 tools/testing/selftests/ftrace/test.d/trigger/trigger-multihist.tc > create mode 100644 tools/testing/selftests/ftrace/test.d/trigger/trigger-snapshot.tc > create mode 100644 tools/testing/selftests/ftrace/test.d/trigger/trigger-stacktrace.tc > create mode 100644 tools/testing/selftests/ftrace/test.d/trigger/trigger-traceonoff.tc > > -- > 1.9.3 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/