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From "Mikhail Fursov" <mike.fur...@gmail.com>
Subject Re: [drlvm][jit] Code review of the following issue - [jira] Commented: (HARMONY-3246) [drlvm][jit][opt] Jitted code can not be executed on non-SSE2 platforms
Date Wed, 18 Apr 2007 17:50:42 GMT
It's a good idea.
I'll do both: add k5 pass to all Jitrino.OPT configs and make EM use
opt.emconf by default.
So there will no additional configuration nor command line options!

On 4/19/07, Gregory Shimansky <gshimansky@gmail.com> wrote:
>
> Rana Dasgupta wrote:
> > Could be a protocol between the EM and the jits, maybe?
>
> I also think that EM is the right place to chose the correct emconf file
> at runtime based on the CPU detection.
>
> > On 4/18/07, Xiao-Feng Li <xiaofeng.li@gmail.com> wrote:
> >> On 4/18/07, Pavel Ozhdikhin <pavel.ozhdikhin@gmail.com> wrote:
> >> > On 4/18/07, Alexey Varlamov <alexey.v.varlamov@gmail.com> wrote:
> >> > >
> >> > > 2007/4/18, Mikhail Fursov <mike.fursov@gmail.com>:
> >> > > > Nathan,
> >> > > > I checked the patch and it looks OK except a one issue.
> >> > > >
> >> > > > I do not really like that we have new p5.emconf in codebase and
> >> propose
> >> > > the
> >> > > > following improvement:
> >> > > > 1) add p5 pass to all Jitrino.OPT codegen aliases in every
> >> emconf we
> >> > > have.
> >> > > > (I can update the patch if agreed)
> >> > > I suppose you meant all ia32 configs :). This is neccesary step to
> >> > > CPUID autodetection, so it a must actually.
> >> > >
> >> > > >
> >> > > > 2) a. After the commit: Make it turned off by default and use
> >> additional
> >> > > > cmd-line -XX:jit.arg.codegen.p5=on when run on PC without SSE2
> >> > > >    b. Start discussion: Use CPUID to detect if SSE2 is available
> >> and
> >> > > make
> >> > > > JIT turn this pass on automatically if needed.
> >> > > >
> >> > > > We can implement CPUID check for SSE2 in JIT only (a couple of
> >> lines of
> >> > > > assembly for Linux and Windows)
> >> > > > The question is: would it be better if VM provides such service
> for
> >> > > every
> >> > > > client? E.g. cpuid_is_sse2_supported()-like methods.
> >> > > I'm in serious doubt that it is needed. Too IA-centric, it would
> have
> >> > > little sense in general case. So doing it right in Jit is the right
> >> > > thing IMO.
> >> >
> >> >
> >> >
> >> > Why do you think this is not needed? We might have several JITs or
> >> > interpreter that can use and extended set of instructions. It would
> >> be good
> >> > to keep these checks in one place in VM.
> >>
> >> This is architecture specific property, hence Alexey may think it
> >> belongs to code generator (here JIT), since otherwise an interpreter
> >> in C may not need it. I think Alexey's point is valid. To deal with
> >> multiple JITs, probably we can put it into some JIT-common files. In
> >> other words, although multiple JITs may query it, it is not
> >> necessarily VM's duty to respond. (Or if we view the JIT-common
> >> support as part of VM, then yes, it can be provided by VM.)
> >>
> >> Thanks,
> >> xiaofeng
> >>
> >> > Thanks,
> >> > Pavel
> >> >
> >> > >
> >> > > >
> >> > > > On 4/18/07, Nathan Beyer <ndbeyer@apache.org> wrote:
> >> > > > >
> >> > > > > Would anyone else like to review this patch? It's somewhat
> >> > > > > significant. I've tested it on a P4/WinXP and DRLVM works
> >> without any
> >> > > > > noticeable regressions. I've done some initial tests on
a Quad
> >> > > > > P3/Ubuntu and I can now run a simple Hello World with the
> >> default JIT,
> >> > > > > which is a huge step.
> >> > > > >
> >> > > > > If no one has any issues, I'm going to commit this patch.
> >> > > > >
> >> > > > > -Nathan
> >> > > > >
> >> > > > > ---------- Forwarded message ----------
> >> > > > > From: Nathan Beyer (JIRA) <jira@apache.org>
> >> > > > > Date: Apr 18, 2007 12:49 AM
> >> > > > > Subject: [jira] Commented: (HARMONY-3246) [drlvm][jit][opt]
> >> Jitted
> >> > > > > code can not be executed on non-SSE2 platforms
> >> > > > > To: commits@harmony.apache.org
> >> > > > >
> >> > > > >
> >> > > > >
> >> > > > >     [
> >> > > > >
> >> > >
> >>
> https://issues.apache.org/jira/browse/HARMONY-3246?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12489614
> >>
> >> > > > > ]
> >> > > > >
> >> > > > > Nathan Beyer commented on HARMONY-3246:
> >> > > > > ---------------------------------------
> >> > > > >
> >> > > > > I've test this on a Linux P3 and it seems to work. I'm now
> >> able to run
> >> > > > > a simple hello world. Additionally, everything seems to
work
> >> as it did
> >> > > > > on a P4/WinXP.
> >> > > > >
> >> > > > > Let's see if we can get a few more people to review the
code.
> >> > > > >
> >> > > > > > [drlvm][jit][opt] Jitted code can not be executed on
non-SSE2
> >> > > platforms
> >> > > > > >
> >> > >
> >> -----------------------------------------------------------------------
> >> > > > > >
> >> > > > > >                 Key: HARMONY-3246
> >> > > > > >                 URL:
> >> > > https://issues.apache.org/jira/browse/HARMONY-3246
> >> > > > > >             Project: Harmony
> >> > > > > >          Issue Type: Improvement
> >> > > > > >          Components: DRLVM
> >> > > > > >            Reporter: Nikolay Sidelnikov
> >> > > > > >         Assigned To: Nathan Beyer
> >> > > > > >         Attachments: p5_fixed_commented.patch
> >> > > > > >
> >> > > > > >
> >> > > > > > Jitrino generates code with SSE and SSE2 instructions
which
> >> can not
> >> > > be
> >> > > > > executed on processors older than Pentium 4.
> >> > > > >
> >> > > > > --
> >> > > > > This message is automatically generated by JIRA.
> >> > > > > -
> >> > > > > You can reply to this email to add a comment to the issue
> online.
> >> > > > >
> >> > > >
> >> > > >
> >> > > >
> >> > > > --
> >> > > > Mikhail Fursov
> >> > > >
> >> > >
> >> >
> >>
> >>
> >> --
> >> http://xiao-feng.blogspot.com
> >>
> >
>
>
> --
> Gregory
>
>


-- 
Mikhail Fursov

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