[Docs][llvm-exegesis] Add documentation on recently added options (#75408)

This patch adds information on the new LLVM-EXEGESIS-SNIPPET-ADDRESS
annotation and on the --benchmark-repeat-count flag.
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Aiden Grossman 2023-12-14 12:07:17 -08:00 committed by GitHub
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@ -81,6 +81,14 @@ properly.
definition should start at. Note that a single memory definition can be
mapped multiple times. Using this annotation requires the subprocess
execution mode.
* `LLVM-EXEGESIS-SNIPPET-ADDRESS <address>` - This annotation allows for
setting the address where the beginning of the snippet to be executed will
be mapped in at. The address is given in hexadecimal. Note that the snippet
also includes setup code, so the instruction exactly at the specified
address will not be the first instruction in the snippet. Using this
annotation requires the subprocess execution mode. This is useful in
cases where the memory accessed by the snippet depends on the location
of the snippet, like RIP-relative addressing.
EXAMPLE 1: benchmarking instructions
------------------------------------
@ -425,6 +433,12 @@ OPTIONS
features such as memory annotations but is currently restricted to X86-64
on Linux.
.. option:: --benchmark-repeat-count=<repeat-count>
This option enables specifying the number of times to repeat the measurement
when performing latency measurements. By default, llvm-exegesis will repeat
a latency measurement enough times to balance run-time and noise reduction.
EXIT STATUS
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