Hi I ran with --js-flags="--crankshaft" and --js-flags="--nocrankshaft" options. But the V8 scores are nearly same.
V8::DisableCrankshaft() function is called from cpu-arm.cc. I think Chromium is not able to parse /proc/cpuinfo file and get VFPv3 information. Arun On Apr 6, 6:31 pm, Rodolph Perfetta <[email protected]> wrote: > Arun, > > Have you tried running Chrome with the options Soren mentioned? The result > should tell you if crankshaft is enabled or not. > > Rodolph. > > 2011/4/6 Víctor M. Jáquez L. <[email protected]> > > > > > > > > > On Wed, Apr 06, 2011 at 12:00:27AM -0700, Arun M wrote: > > > Hi Victor > > > > Will this method of detecting VFPv3 work in chromium browser when > > > sandbox is enabled? > > > Will browser sandbox allow to fopen "/proc/cpuinfo" file? > > > Sorry Arun, I don't know. I'm not familiar with chrome in general. > > > vmjl > > > > Arun > > > > On Apr 4, 6:19 pm, Víctor M. Jáquez L. <[email protected]> wrote: > > > > On Mon, Apr 04, 2011 at 09:45:52AM +0100, Alexandre Rames wrote: > > > > > Hello Arun, > > > > > > Crankshaft is now enabled by default on ARM processors supporting > > VFPv3.. > > > > > v8 does not use NEON (it is not worth using, at least currently), but > > I > > > > > believe no processors with this configuration (NEON without VFPv3) > > exist > > > > > anyway. So if the CPU feature detection work correctly, v8 should > > assume > > > > > that you have VFPv3 if it detects NEON, and thus use use Crankshaft. > > > > > > If I remember correctly there has been some issues with incorrect > > feature > > > > > detection. A simple run of the v8 benchmarks with the latest > > bleeding_edge > > > > > and the frequency of your CPU should be enough to determine if > > crankshaft is > > > > > enabled. > > > > > The CPU features detection is done parsing the /proc/cpuinfo file: > > > > >https://code.google.com/p/v8/source/browse/branches/bleeding_edge/src. > > .. > > > > > So, if your cpu information is not exposed correctly the detection will > > fail. > > > > > I'd never seen an ARM with NEON but without VFPv3. > > > > > vmjl > > > > > > I hope this helps. > > > > > > Regards, > > > > > > Alexandre > > > > > > On Sat, Apr 2, 2011 at 7:40 AM, Arun M <[email protected]> > > wrote: > > > > > > > Hi > > > > > > > Is Crankshaft optimizing compiler enabled for ARMv7-A + NEON > > devices > > > > > > which does not have VFPv3 FPU? > > > > > > > Thanks & Regards > > > > > > Arun > > > > > > > On Mar 9, 6:02 pm, S�ren Gjesse <[email protected]> wrote: > > > > > > > For ARM crankshaft is now the default. This change is in the > > repository > > > > > > > starting from V8 version 3.2. To use the previous optimizing > > compiler > > > > > > > --nocrankshaft will have to be used. When crankshaft for ARM has > > been > > > > > > fully > > > > > > > stabilized the previous optimizing compiler will be removed from > > the > > > > > > > repository and running with --nocrankshaft will no longer be > > possible. > > > > > > There > > > > > > > is no specific date to when this will happen but most likely it > > will be > > > > > > > within a month or two. The removal of the previous optimizing > > compiler > > > > > > will > > > > > > > happen for all supported platforms simultaneously, > > > > > > > > The previous optimizing compiler can of cause still be found in > > previous > > > > > > > versions of V8. > > > > > > > > Regards, > > > > > > > S�ren > > > > > > > > On Tue, Mar 8, 2011 at 20:05, Hugo Vincent < > > [email protected]> > > > > > > wrote: > > > > > > > > How much slower is full-compiler than nocrankshaft on > > ARM926ej-s - > > > > > > > > anyone have any benchmarks? I'm hesitant to invest time in > > using V8 > > > > > > > > for my project if it's going to get substantially slower soon. > > Is > > > > > > > > there any estimated time frame for when nocrankshaft will be > > > > > > > > deprecated? > > > > > > > > > Thanks, > > > > > > > > Hugo > > > > > > > > > On Feb 23, 9:14 pm, S�ren Gjesse <[email protected]> > > wrote: > > > > > > > > > Just a follow-up note regarding the new optimizing compiler > > > > > > (crankshaft). > > > > > > > > > This will be enabled by default for ARM quite soon, and the > > existing > > > > > > > > > optimizing compiler will be removed at some point. For non > > ARMv7+VFP > > > > > > > > devices > > > > > > > > > this means that the base JIT (non-optimizing/full-compiler) > > will be > > > > > > used. > > > > > > > > To > > > > > > > > > measure the different compilers on a ARMv7+VFP device use > > following > > > > > > > > options: > > > > > > > > > > --nocrankshaft (current optimizing JIT - the current > > default) > > > > > > > > > --crankshaft (new optimizing JIT - the soon to be default) > > > > > > > > > --always-full-compiler (base/non-optimizing compiler) > > > > > > > > > > Going forward using --crankshaft on a non ARMv7+VFP device > > will have > > > > > > no > > > > > > > > > effect and execution will fallback to --always-full-compiler. > > > > > > > > > > Regards, > > > > > > > > > S�ren > > > > > > > > > > On Wed, Feb 23, 2011 at 18:33, Rodolph Perfetta > > > > > > > > > <[email protected]>wrote: > > > > > > > > > > > V8 can run on ARMv4 devices (non T though). > > > > > > > > > > > There is no interpreter in V8 so you will be using the JIT > > every > > > > > > time, > > > > > > > > > > perfromance should be good (keep in mind CPU like 926-ej-s > > do not > > > > > > have > > > > > > > > L2 > > > > > > > > > > cache and this is going to have a visible impact). There is > > a new > > > > > > JIT > > > > > > > > > > infrastructure being developed (crankshaft) which features > > an > > > > > > > > optimising JIT > > > > > > > > > > and this will only be for ARMv7+VFP devices. > > > > > > > > > > > HTH, > > > > > > > > > > Rodolph. > > > > > > > > > > > On 23 February 2011 17:12, Hugo Vincent < > > [email protected]> > > > > > > > > wrote: > > > > > > > > > > >> Hi, > > > > > > > > > > >> I can't find in the documentation which ARM architecture > > types V8 > > > > > > > > > >> supports. Does it support older ARM9 devices (I'm > > specifically > > > > > > > > > >> interested in an ARMv5te architecture, ARM926ej-s device) > > or only > > > > > > > > > >> newer ARMv7 (Cortex-A8 etc)? I can see that it is > > (supposed to) > > > > > > build > > > > > > > > > >> on ARMv5te, but do all the JIT features work or is it > > running in a > > > > > > > > > >> byte code interpreter fallback or something? Can I expect > > good > > > > > > > > > >> performance? > > > > > > > > > > >> Thanks, > > > > > > > > > >> Hugo > > > > > > > > > > >> -- > > > > > > > > > >> v8-users mailing list > > > > > > > > > >> [email protected] > > > > > > > > > >>http://groups.google.com/group/v8-users > > > > > > > > > > > -- > > > > > > > > > > v8-users mailing list > > > > > > > > > > [email protected] > > > > > > > > > >http://groups.google.com/group/v8-users > > > > > > > > > -- > > > > > > > > v8-users mailing list > > > > > > > > [email protected] > > > > > > > >http://groups.google.com/group/v8-users > > > > > > > -- > > > > > > v8-users mailing list > > > > > > [email protected] > > > > > >http://groups.google.com/group/v8-users > > > -- > > v8-users mailing list > > [email protected] > >http://groups.google.com/group/v8-users -- v8-users mailing list [email protected] http://groups.google.com/group/v8-users
