Messages in this thread | | | Date | Tue, 21 Jul 2015 18:40:12 +0900 | From | Masami Hiramatsu <> | Subject | Re: [PATCH v9 00/22] tracing: 'hist' triggers |
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Hi Tom,
Thank you for updating your patches, I'm testing it.
And when I'm testing hist trigger, I've found that the .hex modifiers on value doesn't work, but no semantic error.
[root@localhost tracing]# echo 'hist:keys=parent_pid:vals=common_pid.hex' > events/sched/sched_process_fork/trigger [root@localhost tracing]#
[root@localhost tracing]# cat events/sched/sched_process_fork/hist # trigger info: hist:keys=parent_pid:vals=hitcount,common_pid.hex:sort=hitcount:size=2048 [active]
{ parent_pid: 26582 } hitcount: 1 common_pid: 26582 { parent_pid: 11968 } hitcount: 1 common_pid: 11968 { parent_pid: 11956 } hitcount: 2 common_pid: 23912
Totals: Hits: 4 Entries: 3 Dropped: 0
while other modifiers return -EINVAL.
[root@localhost tracing]# echo 'hist:keys=parent_pid:vals=common_pid.execname' > events/sched/sched_process_fork/trigger -bash: echo: write error: Invalid argument
Thank you,
On 2015/07/17 2:22, Tom Zanussi wrote: > This is v9 of the 'hist triggers' patchset. > > 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 b44754d8262d3aab842998cf747f44fe6090be9f: > > ring_buffer: Allow to exit the ring buffer benchmark immediately (2015-06-15 12:03:12 -0400) > > are available in the git repository at: > > git://git.yoctoproject.org/linux-yocto-contrib.git tzanussi/hist-triggers-v9 > http://git.yoctoproject.org/cgit/cgit.cgi/linux-yocto-contrib/log/?h=tzanussi/hist-triggers-v9 > > Namhyung Kim (1): > tracing: Support string type key properly > > Tom Zanussi (21): > 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 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 > > Documentation/trace/events.txt | 1131 +++++++++++++++++++++++++++ > include/linux/trace_events.h | 9 +- > kernel/trace/Kconfig | 14 + > kernel/trace/Makefile | 2 + > kernel/trace/trace.c | 66 ++ > kernel/trace/trace.h | 77 +- > kernel/trace/trace_events.c | 4 + > kernel/trace/trace_events_filter.c | 12 - > kernel/trace/trace_events_hist.c | 1462 +++++++++++++++++++++++++++++++++++ > kernel/trace/trace_events_trigger.c | 149 ++-- > kernel/trace/trace_syscalls.c | 11 + > kernel/trace/tracing_map.c | 935 ++++++++++++++++++++++ > kernel/trace/tracing_map.h | 258 +++++++ > 13 files changed, 4046 insertions(+), 84 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 >
-- Masami HIRAMATSU Linux Technology Research Center, System Productivity Research Dept. Center for Technology Innovation - Systems Engineering Hitachi, Ltd., Research & Development Group E-mail: masami.hiramatsu.pt@hitachi.com
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