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From: Alistair Francis <alistair23@gmail.com>
To: Jonathan Nieder <jrnieder@gmail.com>
Cc: Jim Wilson <jimw@sifive.com>,
	Joseph Myers <joseph@codesourcery.com>,
	 GNU C Library <libc-alpha@sourceware.org>
Subject: Re: Math errors
Date: Tue, 14 Jan 2020 14:57:14 +1000	[thread overview]
Message-ID: <CAKmqyKMLY+r=AfW1XPfdmP3MSUqDKo4JM1M2PHoD1Lh23fqzPQ@mail.gmail.com> (raw)
In-Reply-To: <20200114022856.GA24302@google.com>

On Tue, Jan 14, 2020 at 12:28 PM Jonathan Nieder <jrnieder@gmail.com> wrote:
>
> Hi,
>
> Alistair Francis wrote:
> > On Wed, Jan 8, 2020 at 4:29 AM Jim Wilson <jimw@sifive.com> wrote:
> >> On Mon, Jan 6, 2020 at 5:33 PM Alistair Francis <alistair23@gmail.com> wrote:
>
> >>> I have the latest 5.4.x kernel, I'm not sure if that has it or not.
> >>
> >> I don't know.  I don't follow linux kernel development that closely.
> >> But the failures I sometimes see are test-fenv and test-fpucw which I
> >> don't see in your list.
> >>
> >> I only run glibc testsuite on hardware though, and I've only been
> >> testing rv64gc support.  I haven't tried qemu.  In the RISC-V software
> >> meeting this morning, Palmer mentioned that there are some known
> >> RISC-V qemu FP bugs, for instance fcmp doesn't set the FP reg dirty
> >> bit when an exception flag is set, which could cause a testcase
> >> failure if a context switch happens at the wrong time.  This could
> >
> > I have noticed that running the tests not in parallel gives much better results
>
> Interesting.  Can you provide full "uname -r" output?  What Linux
> distribution do you use?

I don't have it in front of me right now, but it's 5.4.x and built
from OpenEmbedded.

>
> I suspect the issue Jim mentioned is fixed by v5.3-rc5~12^2~1 ("riscv:
> Correct the initialized flow of FP register", 2019-08-14), which you
> would already have.  That said, the 5.5-rc series has some more fp reg
> handling fixes.

It could be a QEMU issue:
https://lists.gnu.org/archive/html/qemu-devel/2020-01/msg02455.html

Alistair

>
> [...]
> >> Someone will have to look at the rv32gc math failures, and keep an
> >> open mind that they could be glibc, qemu, gcc, linux kernel, etc
> >
> > Yeah, that's what I was thinking. There are only a few math tests left
> > failing, so it's not too bad. Thanks for the information Jim.
>
> That it appears more often with threading does suggest some kind of FP
> register leakage.
>
> Thanks and happy hunting,
> Jonathan

  reply	other threads:[~2020-01-14  4:57 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-30 19:52 Math errors Alistair Francis
2019-12-30 22:28 ` Joseph Myers
2019-12-30 22:29   ` Joseph Myers
2020-01-03  2:18     ` Alistair Francis
2020-01-03  9:30       ` Szabolcs Nagy
2020-01-04 18:09         ` Alistair Francis
2020-01-07  1:29       ` Jim Wilson
2020-01-07  1:32         ` Alistair Francis
2020-01-07 18:29           ` Jim Wilson
2020-01-14  2:10             ` Alistair Francis
2020-01-14  2:28               ` Jonathan Nieder
2020-01-14  4:57                 ` Alistair Francis [this message]
2020-01-14  7:28                   ` Alistair Francis

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