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From "Nathan Beyer" <ndbe...@apache.org>
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 Thu, 19 Apr 2007 00:13:42 GMT
On 4/18/07, Mikhail Fursov <mike.fursov@gmail.com> wrote:
> 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!

I'm not sure what all this means, but if the last line means DRLVM
will run and pass its tests on a P3 straight out of the build, then
that's a +1 from me.

Are you going to post a new patch to this bug? Just so I know what to watch for.

-Nathan

>
> 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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