linux.git/include/trace/events/iocost.h, branch vsnprintf

tracing/treewide: Remove second parameter of __assign_str()

2024-05-23T00:14:47+00:00

With the rework of how the __string() handles dynamic strings where it
saves off the source string in field in the helper structure[1], the
assignment of that value to the trace event field is stored in the helper
value and does not need to be passed in again.

This means that with:

  __string(field, mystring)

Which use to be assigned with __assign_str(field, mystring), no longer
needs the second parameter and it is unused. With this, __assign_str()
will now only get a single parameter.

There's over 700 users of __assign_str() and because coccinelle does not
handle the TRACE_EVENT() macro I ended up using the following sed script:

  git grep -l __assign_str | while read a ; do
      sed -e 's/\(__assign_str([^,]*[^ ,]\) *,[^;]*/\1)/' $a > /tmp/test-file;
      mv /tmp/test-file $a;
  done

I then searched for __assign_str() that did not end with ';' as those
were multi line assignments that the sed script above would fail to catch.

Note, the same updates will need to be done for:

  __assign_str_len()
  __assign_rel_str()
  __assign_rel_str_len()

I tested this with both an allmodconfig and an allyesconfig (build only for both).

[1] https://lore.kernel.org/linux-trace-kernel/20240222211442.634192653@goodmis.org/

Link: https://lore.kernel.org/linux-trace-kernel/20240516133454.681ba6a0@rorschach.local.home

Cc: Masami Hiramatsu 
Cc: Mathieu Desnoyers 
Cc: Linus Torvalds 
Cc: Julia Lawall 
Signed-off-by: Steven Rostedt (Google) 
Acked-by: Jani Nikula 
Acked-by: Christian König  for the amdgpu parts.
Acked-by: Thomas Hellström  #for
Acked-by: Rafael J. Wysocki  # for thermal
Acked-by: Takashi Iwai 
Acked-by: Darrick J. Wong 	# xfs
Tested-by: Guenter Roeck

blk-iocost: Trace vtime_base_rate instead of vtime_rate

2022-12-01T14:44:12+00:00

Since commit ac33e91e2daca ("blk-iocost: implement vtime loss
compensation") rename original vtime_rate to vtime_base_rate
and current vtime_rate is original vtime_rate with compensation.
The current rate showed in tracepoint is mixed with vtime_rate
and vtime_base_rate:
1) In function ioc_adjust_base_vrate, the first trace_iocost_ioc_vrate_adj
shows vtime_rate, the second trace_iocost_ioc_vrate_adj shows
vtime_base_rate.
2) In function iocg_activate shows vtime_rate by calling
TRACE_IOCG_PATH(iocg_activate...
3) In function ioc_check_iocgs shows vtime_rate by calling
TRACE_IOCG_PATH(iocg_idle...

Trace vtime_base_rate instead of vtime_rate as:
1) Before commit ac33e91e2daca ("blk-iocost: implement vtime loss
compensation"), the traced rate is without compensation, so still
show rate without compensation.
2) The vtime_base_rate is more stable while vtime_rate heavily depends on
excess budeget on current period which may change abruptly in next period.

Signed-off-by: Kemeng Shi 
Acked-by: Tejun Heo 
Link: https://lore.kernel.org/r/20221018121932.10792-4-shikemeng@huawei.com
Signed-off-by: Jens Axboe

blk-iocost: tracing: atomic64_read(&ioc->vtime_rate) is assigned an extra semicolon

2022-07-12T20:36:37+00:00

Remove extra semicolon.

Link: https://lkml.kernel.org/r/20220629030013.10362-1-kunyu@nfschina.com

Cc: Tejun Heo 
Cc: Jens Axboe 
Signed-off-by: Li kunyu 
Signed-off-by: Steven Rostedt (Google)

blk-iocost: Add iocg idle state tracepoint

2020-12-17T14:55:44+00:00

It will be helpful to trace the iocg's whole state, including active and
idle state. And we can easily expand the original iocost_iocg_activate
trace event to support a state trace class, including active and idle
state tracing.

Acked-by: Tejun Heo 
Signed-off-by: Baolin Wang 
Signed-off-by: Jens Axboe

iocost: add iocg_forgive_debt tracepoint

2020-09-25T14:35:02+00:00

Signed-off-by: Tejun Heo 
Signed-off-by: Jens Axboe

blk-iocost: restore inuse update tracepoints

2020-09-02T01:38:33+00:00

Update and restore the inuse update tracepoints.

Signed-off-by: Tejun Heo 
Signed-off-by: Jens Axboe

blk-iocost: decouple vrate adjustment from surplus transfers

2020-09-02T01:38:32+00:00

Budget donations are inaccurate and could take multiple periods to converge.
To prevent triggering vrate adjustments while surplus transfers were
catching up, vrate adjustment was suppressed if donations were increasing,
which was indicated by non-zero nr_surpluses.

This entangling won't be necessary with the scheduled rewrite of donation
mechanism which will make it precise and immediate. Let's decouple the two
in preparation.

Signed-off-by: Tejun Heo 
Signed-off-by: Jens Axboe

blk-iocost: calculate iocg->usages[] from iocg->local_stat.usage_us

2020-09-02T01:38:32+00:00

Currently, iocg->usages[] which are used to guide inuse adjustments are
calculated from vtime deltas. This, however, assumes that the hierarchical
inuse weight at the time of calculation held for the entire period, which
often isn't true and can lead to significant errors.

Now that we have absolute usage information collected, we can derive
iocg->usages[] from iocg->local_stat.usage_us so that inuse adjustment
decisions are made based on actual absolute usage. The calculated usage is
clamped between 1 and WEIGHT_ONE and WEIGHT_ONE is also used to signal
saturation regardless of the current hierarchical inuse weight.

Signed-off-by: Tejun Heo 
Signed-off-by: Jens Axboe

blk-iocost: Fix error on iocost_ioc_vrate_adj

2020-04-21T15:49:36+00:00

Systemtap 4.2 is unable to correctly interpret the "u32 (*missed_ppm)[2]"
argument of the iocost_ioc_vrate_adj trace entry defined in
include/trace/events/iocost.h leading to the following error:

  /tmp/stapAcz0G0/stap_c89c58b83cea1724e26395efa9ed4939_6321_aux_6.c:78:8:
  error: expected ‘;’, ‘,’ or ‘)’ before ‘*’ token
   , u32[]* __tracepoint_arg_missed_ppm

That argument type is indeed rather complex and hard to read. Looking
at block/blk-iocost.c. It is just a 2-entry u32 array. By simplifying
the argument to a simple "u32 *missed_ppm" and adjusting the trace
entry accordingly, the compilation error was gone.

Fixes: 7caa47151ab2 ("blkcg: implement blk-iocost")
Acked-by: Steven Rostedt (VMware) 
Acked-by: Tejun Heo 
Signed-off-by: Waiman Long 
Signed-off-by: Jens Axboe

blkcg: blk-iocost: predeclare used structs

2019-08-29T15:43:34+00:00

Fixes: 7caa47151ab2 ("blkcg: implement blk-iocost")
Acked-by: Tejun Heo 
Signed-off-by: Stephen Rothwell 
Signed-off-by: Jens Axboe