| Message ID | 20161127201707.3789-2-me@tobias.gr |
|---|---|
| State | New |
| Headers | show |
On Sun, Nov 27, 2016 at 09:17:07PM +0100, Tobias Geerinckx-Rice wrote: > * gnu/packages/gnuzilla.scm (icecat)[source]: Remove bundled libjpeg. > [inputs]: Add libjpeg-turbo. > [arguments]: Use it. > - ;; Fails with "libjpeg-turbo JCS_EXTENSIONS > - ;; required". > - ;; According to > - ;; http://sourceforge.net/projects/libjpeg-turbo/ , > - ;; "libjpeg-turbo is a derivative of libjpeg that > - ;; uses MMX, SSE, SSE2, and NEON SIMD instructions > - ;; to accelerate baseline JPEG compression/ > - ;; decompression", so we had better not use it > - ;; "--with-system-jpeg" Will this work on nachines that don't support SSE? My understanding is that we don't wish to require it.
Leo, On 27/11/16 21:56, Leo Famulari wrote: > Will this work on nachines that don't support SSE? My understanding is > that we don't wish to require it. Why wouldn't it? I don't often use Icecat, but when I do... I don't see why it would require SSE by default. ;-) And it's not like we ever patched it to use IJG's libjpeg to begin with. Kind regards, T G-R
On Sun, Nov 27, 2016 at 10:02:35PM +0100, Tobias Geerinckx-Rice wrote: > Leo, > > On 27/11/16 21:56, Leo Famulari wrote: > > Will this work on nachines that don't support SSE? My understanding is > > that we don't wish to require it. > > Why wouldn't it? > > I don't often use Icecat, but when I do... I don't see why it would > require SSE by default. ;-) And it's not like we ever patched it to use > IJG's libjpeg to begin with. I'm not sure, but the comment seems to indicate that we don't want to use it: ;; According to ;; http://sourceforge.net/projects/libjpeg-turbo/ , ;; "libjpeg-turbo is a derivative of libjpeg that ;; uses MMX, SSE, SSE2, and NEON SIMD instructions ;; to accelerate baseline JPEG compression/ ;; decompression", so we had better not use it But I'm not sure how to interpret that, so I've copied Andreas on my reply (he wrote that comment).
Leo Famulari <leo@famulari.name> writes: > On Sun, Nov 27, 2016 at 10:02:35PM +0100, Tobias Geerinckx-Rice wrote: >> Leo, >> >> On 27/11/16 21:56, Leo Famulari wrote: >> > Will this work on nachines that don't support SSE? My understanding is >> > that we don't wish to require it. >> >> Why wouldn't it? >> >> I don't often use Icecat, but when I do... I don't see why it would >> require SSE by default. ;-) And it's not like we ever patched it to use >> IJG's libjpeg to begin with. > > I'm not sure, but the comment seems to indicate that we don't want to > use it: > > ;; According to > ;; http://sourceforge.net/projects/libjpeg-turbo/ , > ;; "libjpeg-turbo is a derivative of libjpeg that > ;; uses MMX, SSE, SSE2, and NEON SIMD instructions > ;; to accelerate baseline JPEG compression/ > ;; decompression", so we had better not use it SSE is pentium III, and SSE2 was introduced in Pentium IV. MMX is even older. Are we really committed to supporting 15+ year old hardware? The NEON SIMD instruction seems to be ARM-specific and is available at least on Cortex A8, which is an ARMv7 design.
Marius Bakke <mbakke@fastmail.com> writes: > Leo Famulari <leo@famulari.name> writes: > >> On Sun, Nov 27, 2016 at 10:02:35PM +0100, Tobias Geerinckx-Rice wrote: >>> Leo, >>> >>> On 27/11/16 21:56, Leo Famulari wrote: >>> > Will this work on nachines that don't support SSE? My understanding is >>> > that we don't wish to require it. >>> >>> Why wouldn't it? >>> >>> I don't often use Icecat, but when I do... I don't see why it would >>> require SSE by default. ;-) And it's not like we ever patched it to use >>> IJG's libjpeg to begin with. >> >> I'm not sure, but the comment seems to indicate that we don't want to >> use it: >> >> ;; According to >> ;; http://sourceforge.net/projects/libjpeg-turbo/ , >> ;; "libjpeg-turbo is a derivative of libjpeg that >> ;; uses MMX, SSE, SSE2, and NEON SIMD instructions >> ;; to accelerate baseline JPEG compression/ >> ;; decompression", so we had better not use it > > SSE is pentium III, and SSE2 was introduced in Pentium IV. MMX is even > older. Are we really committed to supporting 15+ year old hardware? Digging a bit further, SSE2 is actually part of the AMD64 specification[0]. Perhaps we could make it conditional on architecture? 0: https://en.wikipedia.org/wiki/SSE2#CPU_support
On Sun, Nov 27, 2016 at 10:50:35PM +0100, Marius Bakke wrote: > Leo Famulari <leo@famulari.name> writes: > > I'm not sure, but the comment seems to indicate that we don't want to > > use it: > > > > ;; According to > > ;; http://sourceforge.net/projects/libjpeg-turbo/ , > > ;; "libjpeg-turbo is a derivative of libjpeg that > > ;; uses MMX, SSE, SSE2, and NEON SIMD instructions > > ;; to accelerate baseline JPEG compression/ > > ;; decompression", so we had better not use it > > SSE is pentium III, and SSE2 was introduced in Pentium IV. MMX is even > older. Are we really committed to supporting 15+ year old hardware? See this earlier thread: http://lists.gnu.org/archive/html/guix-devel/2016-07/msg01534.html I think it's fine to use libjpeg-turbo if it can run on those older processors, or if we decide to drop support for them. > The NEON SIMD instruction seems to be ARM-specific and is available at > least on Cortex A8, which is an ARMv7 design. The extremely popular Cortex A7 [0] also has NEON SIMD. [0] Allwinner A20
On Sun, Nov 27, 2016 at 11:28:45PM +0100, Marius Bakke wrote: > Marius Bakke <mbakke@fastmail.com> writes: > > > Leo Famulari <leo@famulari.name> writes: > > > >> On Sun, Nov 27, 2016 at 10:02:35PM +0100, Tobias Geerinckx-Rice wrote: > >>> Leo, > >>> > >>> On 27/11/16 21:56, Leo Famulari wrote: > >>> > Will this work on nachines that don't support SSE? My understanding is > >>> > that we don't wish to require it. > >>> > >>> Why wouldn't it? > >>> > >>> I don't often use Icecat, but when I do... I don't see why it would > >>> require SSE by default. ;-) And it's not like we ever patched it to use > >>> IJG's libjpeg to begin with. > >> > >> I'm not sure, but the comment seems to indicate that we don't want to > >> use it: > >> > >> ;; According to > >> ;; http://sourceforge.net/projects/libjpeg-turbo/ , > >> ;; "libjpeg-turbo is a derivative of libjpeg that > >> ;; uses MMX, SSE, SSE2, and NEON SIMD instructions > >> ;; to accelerate baseline JPEG compression/ > >> ;; decompression", so we had better not use it > > > > SSE is pentium III, and SSE2 was introduced in Pentium IV. MMX is even > > older. Are we really committed to supporting 15+ year old hardware? > > Digging a bit further, SSE2 is actually part of the AMD64 > specification[0]. Perhaps we could make it conditional on architecture? > > 0: https://en.wikipedia.org/wiki/SSE2#CPU_support Sure, if it requires SSE2 to run, and we keep the status quo regarding i686, I don't see why not.
Andreas, Leo, Thanks for the feedback! On 27/11/16 22:41, Leo Famulari wrote: > I'm not sure, but the comment seems to indicate that we don't want to > use it: > > ;; According to > ;; http://sourceforge.net/projects/libjpeg-turbo/ , > ;; "libjpeg-turbo is a derivative of libjpeg that > ;; uses MMX, SSE, SSE2, and NEON SIMD instructions > ;; to accelerate baseline JPEG compression/ > ;; decompression", so we had better not use it There seems to be some misunderstanding here. Sorry if it wasn't clear: this (libjpeg-turbo) was *already* bundled and used by icecat, as the ‘media/libjpeg’ (sic) that this patch removes. You'll find the same SIMD code there. For the quote above is missing: > ;; Fails with "libjpeg-turbo JCS_EXTENSIONS required". Translation: icecat wouldn't build with Guix's ‘libjpeg’ even if we'd want that. And we don't. This isn't some dodgy go-faster fork of IJG's ‘real’ libjpeg. It's intended as a sane alternative to the IJG library, albeit one that doesn't implement every recent extension. It detects CPU features at runtime — although they're the status quo now, as Andreas notes — and falls back to other algorithms that might still be faster. Dang it. I thought I wrote good (description)s. :-( Kind regards, T G-R-turbo
On 28/11/16 00:15, Tobias Geerinckx-Rice wrote:
> this (libjpeg-turbo) was *already* bundled and used by icecat, [...]
Some fortuitous grepping revealed that our spice packages also #warns
about *not* being built with libjpeg-turbo. Absent any known drawbacks,
I'd follow upstreams' recommendations in these matters.
Kind regards,
T G-R
On Mon, Nov 28, 2016 at 12:15:01AM +0100, Tobias Geerinckx-Rice wrote: > There seems to be some misunderstanding here. Sorry if it wasn't clear: > this (libjpeg-turbo) was *already* bundled and used by icecat, as the > ‘media/libjpeg’ (sic) that this patch removes. You'll find the same SIMD > code there. For the quote above is missing: Ah, thanks for the clarification. > > ;; Fails with "libjpeg-turbo JCS_EXTENSIONS required". > > Translation: icecat wouldn't build with Guix's ‘libjpeg’ even if we'd > want that. > > And we don't. This isn't some dodgy go-faster fork of IJG's ‘real’ > libjpeg. It's intended as a sane alternative to the IJG library, albeit > one that doesn't implement every recent extension. It detects CPU > features at runtime — although they're the status quo now, as Andreas > notes — and falls back to other algorithms that might still be faster. > > Dang it. I thought I wrote good (description)s. :-( The description is excellent. Thanks for putting up with my misunderstanding :)
On Mon, Nov 28, 2016 at 12:20:53AM +0100, Tobias Geerinckx-Rice wrote: > On 28/11/16 00:15, Tobias Geerinckx-Rice wrote: > > this (libjpeg-turbo) was *already* bundled and used by icecat, [...] > > Some fortuitous grepping revealed that our spice packages also #warns > about *not* being built with libjpeg-turbo. Absent any known drawbacks, > I'd follow upstreams' recommendations in these matters. Now that we have the package, I think we should make spice use it.
diff --git a/gnu/packages/gnuzilla.scm b/gnu/packages/gnuzilla.scm index 3b00d3c..f7a8c7d 100644 --- a/gnu/packages/gnuzilla.scm +++ b/gnu/packages/gnuzilla.scm @@ -403,6 +403,7 @@ standards.") "modules/zlib" "modules/libbz2" "ipc/chromium/src/third_party/libevent" + "media/libjpeg" "media/libvpx" "security/nss" "gfx/cairo" @@ -432,6 +433,7 @@ standards.") ("hunspell" ,hunspell) ("libcanberra" ,libcanberra) ("libgnome" ,libgnome) + ("libjpeg-turbo" ,libjpeg-turbo) ("libxft" ,libxft) ("libevent" ,libevent) ("libxinerama" ,libxinerama) @@ -497,6 +499,7 @@ standards.") ;; Avoid bundled libraries. "--with-system-zlib" "--with-system-bz2" + "--with-system-jpeg" ; must be libjpeg-turbo "--with-system-libevent" "--with-system-libvpx" "--with-system-icu" @@ -517,16 +520,6 @@ standards.") ;; Network Graphics (PNG) format"; ;; we probably do not wish to support it. ;; "--with-system-png" - - ;; Fails with "libjpeg-turbo JCS_EXTENSIONS - ;; required". - ;; According to - ;; http://sourceforge.net/projects/libjpeg-turbo/ , - ;; "libjpeg-turbo is a derivative of libjpeg that - ;; uses MMX, SSE, SSE2, and NEON SIMD instructions - ;; to accelerate baseline JPEG compression/ - ;; decompression", so we had better not use it - ;; "--with-system-jpeg" ) #:modules ((ice-9 ftw)