Hello, Based on a suggestion from Alex earlier this week, I managed to run a simple benchmark of softfloat performance with qemu-arm, as requested by Peter.
I went for the Whetstone floating point benchmark: http://en.wikipedia.org/wiki/Whetstone_%28benchmark%29 For a loop count of 100,000 and 5 runs I got the following results: current: 138.9-204.1 Whetstone-MIPS [u]int*_t: 185.2-188.7 Whetstone-MIPS [u]int_fast*_t: 285.7-294.1 Whetstone-MIPS Toshiba AC100: 833.3-909.1 Whetstone-MIPS These results seem to indicate that the "fast" POSIX types are indeed somewhat faster, both compared to exact-size POSIX types and to the current state. As a short summary of previous discussions, softfloat had these typedefs: [s]bits{8,16,32,64} - exact-size semantics, => [u]int{8,16,32,64}_t [u]int{8,16,32,64} - minimum-width semantics, host-independent AIX, Mac OS X and BeOS/Haiku have some or all of the latter already, leading to type conflicts. I had originally suggested the POSIX [u]int_least*_t types but we rather preferred [u]int_fast*_t, worried about performance, to get the fastest least-width types. For either of these the actual width depends on system headers. On the other hand it would be futile to try to performance-optimize integer types for every possible host inside QEMU. If we don't mind performance or dislike host-dependencies, we could just use [u]int*_t, but then with everything [u]int*_t we can't easily change this in case it bites us in the future. Personally I prefer those 'fast' types, because that way we get to keep the distinction between what was formerly [s]bits* and [u]int* types. The clear name distinction would even allow to do conversions by regex. However, I noticed that target-mips/cpu.h had typedefs for uint_fast{8,16}_t for Solaris <= 9. So I moved these to osdep.h and added typedefs for the newly needed types. Coccinelle needed some tweaking for the macros and only did the uint16 conversion fully. For the others I was too impatient, so I hand-converted the remaining occurrences that Coccinelle did not catch. Since Coccinelle stripped leading whitespace before types replaced anyway, I hand-edited (and git-am'ed) the patches to make lines touched adhere to Coding Style. Patches 1-3 fix misuses of softfloat types that were introduced since the last series of fixes. These could be cherry-picked. Patch 4 fixes a misuse of int inside softfloat. This could be cherry-picked. Patch 5 moves the Solaris typedefs to a central header, resolving an XXX present since their introduction in r1979. Patches 6-13 convert the softfloat integer types. Patch 14 converts the 'flag' type to bool, removing the last softfloat type. Please test that this doesn't break / unbreaks Your Favorite Host: http://repo.or.cz/w/qemu/afaerber.git/shortlog/refs/heads/softfloat Regards, Andreas Cc: Alexander Graf <ag...@suse.de> Cc: Peter Maydell <peter.mayd...@linaro.org> Cc: Aurélien Jarno <aurel...@aurel32.net> Cc: malc <av1...@comtv.ru> Cc: Ben Taylor <bentaylor.sol...@gmail.com> Cc: Rui Carmo <rui.ca...@gmail.com> Cc: Eric Sunshine <sunsh...@sunshineco.com> Cc: Pavel Borzenkov <pavel.borzen...@gmail.com> Cc: Juan Pineda <j...@logician.com> Host: HP Envy w/ Intel Core i7-2630QM 2.0 GHz (openSUSE 12.1) QEMU: 2be276242135eac6e86be2a8259545e620c94107 plus + 2 patches Configuration: --prefix=/usr/local Command: arm-linux-user/qemu-arm path/to/whetstone -c 100000 Source: http://www.netlib.org/benchmark/whetstone.c Compiler: gcc (Ubuntu/Linaro 4.4.4-14ubuntu5) 4.4.5 Compilation: gcc -O -s whetstone.c -o whetstone -lm -static [u]int*_t: --- diff --git a/fpu/softfloat.h b/fpu/softfloat.h index 07c2929..6fe19d7 100644 --- a/fpu/softfloat.h +++ b/fpu/softfloat.h @@ -57,11 +57,11 @@ typedef uint8_t flag; typedef uint8_t uint8; typedef int8_t int8; #ifndef _AIX -typedef int uint16; -typedef int int16; +typedef uint16_t uint16; +typedef int16_t int16; #endif -typedef unsigned int uint32; -typedef signed int int32; +typedef uint32_t uint32; +typedef int32_t int32; typedef uint64_t uint64; typedef int64_t int64; --- [u]int_fast*_t: --- diff --git a/fpu/softfloat.h b/fpu/softfloat.h index 07c2929..43486aa 100644 --- a/fpu/softfloat.h +++ b/fpu/softfloat.h @@ -54,16 +54,16 @@ these four paragraphs for those parts of this code that are retained. | to the same as `int'. *----------------------------------------------------------------------------*/ typedef uint8_t flag; -typedef uint8_t uint8; -typedef int8_t int8; +typedef uint_fast8_t uint8; +typedef int_fast8_t int8; #ifndef _AIX -typedef int uint16; -typedef int int16; +typedef uint_fast16_t uint16; +typedef int_fast16_t int16; #endif -typedef unsigned int uint32; -typedef signed int int32; -typedef uint64_t uint64; -typedef int64_t int64; +typedef uint_fast32_t uint32; +typedef int_fast32_t int32; +typedef uint_fast64_t uint64; +typedef int_fast64_t int64; #define LIT64( a ) a##LL #define INLINE static inline --- spatch(1) -macro_file_builtins: --- #define STATUS_PARAM #define STATUS_VAR #define INLINE static inline #define MINMAX --- Andreas Färber (13): lm32: Fix mixup of uint32 and uint32_t target-sparc: Fix mixup of uint64 and uint64_t qemu-tool: Fix mixup of int64 and int64_t softfloat: Fix mixups of int and int16 softfloat: Replace uint16 type with uint_fast16_t softfloat: Replace int16 type with int_fast16_t softfloat: Remove unused uint8 type softfloat: Replace int8 type with int_fast8_t softfloat: Replace uint32 type with uint_fast32_t softfloat: Replace int32 type with int_fast32_t softfloat: Replace uint64 type with uint_fast64_t softfloat: Replace int64 type with int_fast64_t softfloat: Replace flag type with bool fpu/softfloat-macros.h | 52 ++-- fpu/softfloat-specialize.h | 56 ++-- fpu/softfloat.c | 626 ++++++++++++++++++++-------------------- fpu/softfloat.h | 115 ++++----- hw/milkymist-vgafb_template.h | 2 +- qemu-tool.c | 4 +- target-sparc/vis_helper.c | 2 +- 7 files changed, 419 insertions(+), 438 deletions(-) -- 1.7.7
