Am 22.01.21 um 10:47 schrieb Thomas Huth:
On 22/01/2021 10.46, Philippe Mathieu-Daudé wrote:
On Fri, Jan 22, 2021 at 10:43 AM Thomas Huth <[email protected]> wrote:
On 22/01/2021 10.22, Philippe Mathieu-Daudé wrote:
Some new users get confused with 'TCG' and 'TCI', and enable TCI
support expecting to enable TCG.
Emit a warning when native TCG backend is available on the
host architecture, mentioning this is a suboptimal configuration.
Signed-off-by: Philippe Mathieu-Daudé <[email protected]>
---
meson.build | 3 +++
1 file changed, 3 insertions(+)
diff --git a/meson.build b/meson.build
index 0a645e54662..7aa52d306c6 100644
--- a/meson.build
+++ b/meson.build
@@ -234,6 +234,9 @@
error('Unsupported CPU @0@, try
--enable-tcg-interpreter'.format(cpu))
endif
endif
+ if 'CONFIG_TCG_INTERPRETER' in config_host and cpu in
supported_cpus
+ warning('Experimental TCI requested while native TCG is
available on @0@, suboptimal performance expected'.format(cpu))
+ endif
accelerators += 'CONFIG_TCG'
config_host += { 'CONFIG_TCG': 'y' }
endif
Reviewed-by: Thomas Huth <[email protected]>
... maybe you could also add some wording to the help text of the
configure
script? Or maybe we could simply rename the "--enable-tcg-interpreter"
option into "--enable-tci" to avoid confusion with the normal TCG ?
I also thought about renaming as --enable-experimental-tci but then
doubt that
would help, some users just want to enable everything :)
Then we should rename it into --disable-native-tcg ;-)
Thomas
Both patches are fine (also optionally with the suggested addition of
"slow"), so
Reviewed-by: Stefan Weil <[email protected]>
I think that --enable-tci would increase the TCI/TCG confusion and
suggest to keep the current --enable-tcg-interpreter as most experts
know that an interpreter is usually something which is slow.
As soon as time permits I also plan to make a new effort to integrate
TCI as a run time option. Some years ago it was not possible to have
code which supports both native and interpreted TCG, but this might have
changed now. If it is possible, this would simplify CI a lot, and users
could select the interpreter via a command line argument.
Stefan
