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doc: fix typos in trace.rst

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Fix obvious typos. Use US spelling consistently.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
This commit is contained in:
Heinrich Schuchardt
2021-11-16 18:38:47 +01:00
parent dfec0e9d9c
commit 3f80064fd5
1 changed files with 8 additions and 8 deletions
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doc/develop/trace.rst
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@@ -4,7 +4,7 @@
Tracing in U-Boot Tracing in U-Boot
================= =================
U-Boot supports a simple tracing feature which allows a record of excecution U-Boot supports a simple tracing feature which allows a record of execution
to be collected and sent to a host machine for analysis. At present the to be collected and sent to a host machine for analysis. At present the
main use for this is to profile boot time. main use for this is to profile boot time.
@@ -161,10 +161,10 @@ limit of the trace buffer size you have specified. Once that is exhausted
no more data will be collected. no more data will be collected.
Collecting trace data has an affect on execution time/performance. You Collecting trace data has an affect on execution time/performance. You
will notice this particularly with trvial functions - the overhead of will notice this particularly with trivial functions - the overhead of
recording their execution may even exceed their normal execution time. recording their execution may even exceed their normal execution time.
In practice this doesn't matter much so long as you are aware of the In practice this doesn't matter much so long as you are aware of the
effect. Once you have done your optimisations, turn off tracing before effect. Once you have done your optimizations, turn off tracing before
doing end-to-end timing. doing end-to-end timing.
The best time to start tracing is right at the beginning of U-Boot. The The best time to start tracing is right at the beginning of U-Boot. The
@@ -184,7 +184,7 @@ the OS. In practical terms, U-Boot runs the 'fakegocmd' environment
variable at this point. This variable should have a short script which variable at this point. This variable should have a short script which
collects the trace data and writes it somewhere. collects the trace data and writes it somewhere.
Trace data collection relies on a microsecond timer, accesed through Trace data collection relies on a microsecond timer, accessed through
timer_get_us(). So the first think you should do is make sure that timer_get_us(). So the first think you should do is make sure that
this produces sensible results for your board. Suitable sources for this produces sensible results for your board. Suitable sources for
this timer include high resolution timers, PWMs or profile timers if this timer include high resolution timers, PWMs or profile timers if
@@ -285,7 +285,7 @@ Options
Specify U-Boot map file Specify U-Boot map file
-p <trace_file> -p <trace_file>
Specifiy profile/trace file Specify profile/trace file
Commands: Commands:
@@ -315,11 +315,11 @@ time:
2. Build U-Boot with tracing and run it. Note the difference in boot time 2. Build U-Boot with tracing and run it. Note the difference in boot time
(it is common for tracing to add 10% to the time) (it is common for tracing to add 10% to the time)
3. Collect the trace information as descibed above. Use this to find where 3. Collect the trace information as described above. Use this to find where
all the time is being spent. all the time is being spent.
4. Take a look at that code and see if you can optimise it. Perhaps it is 4. Take a look at that code and see if you can optimize it. Perhaps it is
possible to speed up the initialisation of a device, or remove an unused possible to speed up the initialization of a device, or remove an unused
feature. feature.
5. Rebuild, run and collect again. Compare your results. 5. Rebuild, run and collect again. Compare your results.