| Age | Commit message (Collapse) | Author |
|---|
|
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull RTLA updates from Steven Rostedt:
- Simplify option parsing
Auto-generate getopt_long() optstring for short options from long
options array, avoiding the need to specify it manually and reducing
the surface for mistakes.
- Add unit tests
Implement unit tests (make unit-tests) using libcheck, next to
existing runtime tests (make check). Currently, three functions from
utils.c are tested.
- Add --stack-format option
In addition to stopping stack pointer decoding (with -s/--stack
option) on first unresolvable pointer, allow also skipping
unresolvable pointers and displaying everything, configurable with a
new option.
- Unify number of CPUs into one global variable
Use one global variable, nr_cpus, to store the number of CPUs instead
of retrieving it and passing it at multiple places.
- Fix behavior in various corner cases
Make RTLA behave correctly in several corner cases: memory allocation
failure, invalid value read from kernel side, thread creation
failure, malformed time value input, and read/write failure or
interruption by signal.
- Improve string handling
Simplify several places in the code that handle strings, including
parsing of action arguments. A few new helper functions and variables
are added for that purpose.
- Get rid of magic numbers
Few places handling paths use a magic number of 1024. Replace it with
MAX_PATH and ARRAY_SIZE() macro.
- Unify threshold handling
Code that handles response to latency threshold is duplicated between
tools, which has led to bugs in the past. Unify it into a new helper
as much as possible.
- Fix segfault on SIGINT during cleanup
The SIGINT handler touches dynamically allocated memory. Detach it
before freeing it during cleanup to prevent segmentation fault and
discarding of output buffers. Also, properly document SIGINT handling
while at it.
* tag 'trace-rtla-v7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (28 commits)
Documentation/rtla: Document SIGINT behavior
rtla: Fix segfault on multiple SIGINTs
rtla/utils: Fix loop condition in PID validation
rtla/utils: Fix resource leak in set_comm_sched_attr()
rtla/trace: Fix I/O handling in save_trace_to_file()
rtla/trace: Fix write loop in trace_event_save_hist()
rtla/timerlat: Simplify RTLA_NO_BPF environment variable check
rtla: Use str_has_prefix() for option prefix check
rtla: Enforce exact match for time unit suffixes
rtla: Use str_has_prefix() for prefix checks
rtla: Add str_has_prefix() helper function
rtla: Handle pthread_create() failure properly
rtla/timerlat: Add bounds check for softirq vector
rtla: Simplify code by caching string lengths
rtla: Replace magic number with MAX_PATH
rtla: Introduce common_threshold_handler() helper
rtla/actions: Simplify argument parsing
rtla: Use strdup() to simplify code
rtla: Exit on memory allocation failures during initialization
tools/rtla: Remove unneeded nr_cpus from for_each_monitored_cpu
...
|
|
rtla supports building without libbpf. However, BPF actions
patchset [1] adds an include of bpf/libbpf.h into timerlat_bpf.h,
which breaks build on systems that don't have libbpf headers
installed.
This is a leftover from a draft version of the patchset where
timerlat_bpf_set_action() (which takes a struct bpf_program * argument)
was defined in the header. timerlat_bpf.c already includes bpf/libbpf.h
via timerlat.skel.h when libbpf is present.
Remove the redundant include to fix build on systems without libbpf
headers.
[1] https://lore.kernel.org/linux-trace-kernel/20251126144205.331954-1-tglozar@redhat.com/T/
Cc: John Kacur <jkacur@redhat.com>
Cc: Luis Goncalves <lgoncalv@redhat.com>
Cc: Crystal Wood <crwood@redhat.com>
Cc: Costa Shulyupin <costa.shul@redhat.com>
Link: https://patch.msgid.link/20260330091207.16184-1-tglozar@redhat.com
Reported-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Closes: https://lore.kernel.org/linux-trace-kernel/20260329122202.65a8b575@robin/
Fixes: 8cd0f08ac72e ("rtla/timerlat: Support tail call from BPF program")
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
Reviewed-by: Wander Lairson Costa <wander@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
|
|
nr_cpus does not change at runtime, so passing it through function
arguments is unnecessary.
Use the global nr_cpus instead of propagating it via parameters.
Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
Link: https://lore.kernel.org/r/20260306194953.2511960-3-costa.shul@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
|
|
Add option --bpf-action that allows the user to attach an external BPF
program that will be executed via BPF tail call on latency threshold
overflow.
Executing additional BPF code on latency threshold overflow allows doing
low-latency and in-kernel troubleshooting of the cause of the overflow.
The option takes an argument, which is a path to a BPF ELF file
expected to contain a function named "action_handler" in a section named
"tp/timerlat_action" (the section is necessary for libbpf to assign the
correct BPF program type to it).
Link: https://lore.kernel.org/r/20251126144205.331954-3-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
|
|
Add a map to the rtla-timerlat BPF program that holds a file descriptor
of another BPF program, to be executed on threshold overflow.
timerlat_bpf_set_action() is added as an interface to set the program.
Link: https://lore.kernel.org/r/20251126144205.331954-2-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
|
|
Currently, rtla-timerlat BPF program uses a global variable stored in a
.bss section to store whether tracing has been stopped.
Move the information to a separate map, so that it is easily writable
from userspace, and add a function that clears the value, resuming
tracing after it has been stopped.
Cc: John Kacur <jkacur@redhat.com>
Cc: Luis Goncalves <lgoncalv@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Chang Yin <cyin@redhat.com>
Cc: Costa Shulyupin <costa.shul@redhat.com>
Cc: Crystal Wood <crwood@redhat.com>
Cc: Gabriele Monaco <gmonaco@redhat.com>
Link: https://lore.kernel.org/20250626123405.1496931-4-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
|
|
Add BPF program that attaches to the osnoise:timerlat_sample tracepoint
and collects both the summary and the histogram (if requested) into BPF
maps (one map of each kind per context).
The program is designed to be used for both timerlat-top and
timerlat-hist. If using with timerlat-top, the "entries" parameter is
set to zero, which prevents the BPF program from recording histogram
entries. In that case, the maps for histograms do not have to be
created, as the BPF verifier will identify the code using them as
unreachable.
An IRQ or thread latency threshold might be supplied to stop recording
if hit, similar to the timerlat tracer threshold, which stops ftrace
tracing if hit. A BPF ringbuffer is used to signal threshold overflow to
userspace. In aa-only mode, this is the only function of the BPF
program.
Cc: John Kacur <jkacur@redhat.com>
Cc: Luis Goncalves <lgoncalv@redhat.com>
Cc: Gabriele Monaco <gmonaco@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Link: https://lore.kernel.org/20250218145859.27762-5-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
|
