Re: [Qemu-devel] [RFC][PATCH v2 4/4] configure: add CONFIG_QEMU_LDST_OPTIMIZATION for TCG qemu_ld/st optimization

[Evgeny Voevodin <e.voevodin@samsung.com>]

On 05.07.2012 17:55, Andreas Färber wrote:
> Am 05.07.2012 15:23, schrieb Yeongkyoon Lee:
>> Add an option "--enable-ldst-optimization" to enable CONFIG_QEMU_LDST_OPTIMIZATION macro for TCG qemu_ld/st optimization. It only works with CONFIG_SOFTMMU and doesn't work with CONFIG_TCG_PASS_AREG0.
>>
>> Signed-off-by: Yeongkyoon Lee <yeongkyoon.lee@samsung.com>
>> ---
>>   configure |   15 +++++++++++++++
>>   1 files changed, 15 insertions(+), 0 deletions(-)
>>
>> diff --git a/configure b/configure
>> index 9f071b7..2b364cc 100755
>> --- a/configure
>> +++ b/configure
> [...]
>> @@ -3463,6 +3466,11 @@ echo "EXESUF=$EXESUF" >> $config_host_mak
>>   echo "LIBS_QGA+=$libs_qga" >> $config_host_mak
>>   echo "POD2MAN=$POD2MAN" >> $config_host_mak
>>   
>> +if [ "$ldst_optimization" = "yes" -a "$cpu" != "i386" -a "$cpu" != "x86_64" ] ; then
>> +  echo "ERROR: qemu_ld/st optimization is only available on i386 or x86_64 hosts"
>> +  exit 1
>> +fi
> [snip]
>
> I assume that Samsung is interested in optimizing the Exynos emulation.

Nope ) Originally it's from x86 Tizen emulator )

> I think there was already a patchset posted converting target-arm to
> CONFIG_PASS_TCG_AREG0, only with some slowdowns to be investigated...
> What is the obstacle for supporting AREG0 mode in your optimization?
>
> Regards,
> Andreas
>
>> +
>>   # generate list of library paths for linker script
>>   
>>   $ld --verbose -v 2> /dev/null | grep SEARCH_DIR > ${config_host_ld}
>> @@ -3696,11 +3704,18 @@ fi
>>   symlink "$source_path/Makefile.target" "$target_dir/Makefile"
>>   
>>   
>> +target_ldst_optimization="$ldst_optimization"
>> +
>>   case "$target_arch2" in
>>     alpha | sparc* | xtensa* | ppc*)
>>       echo "CONFIG_TCG_PASS_AREG0=y" >> $config_target_mak
>> +    # qemu_ld/st optimization is not available with CONFIG_TCG_PASS_AREG0
>> +    target_ldst_optimization="no"
>>     ;;
>>   esac
>> +if [ "$target_ldst_optimization" = "yes" -a "$target_softmmu" = "yes" ] ; then
>> +    echo "CONFIG_QEMU_LDST_OPTIMIZATION=y" >> $config_target_mak
>> +fi
>>   
>>   echo "TARGET_SHORT_ALIGNMENT=$target_short_alignment" >> $config_target_mak
>>   echo "TARGET_INT_ALIGNMENT=$target_int_alignment" >> $config_target_mak


-- 
Kind regards,
Evgeny Voevodin,
Technical Leader,
Mobile Group, SMRC, Samsung Electronics
e-mail: e.voevodin@samsung.com