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Re: [PULL 00/17] NBD patches through 2021-03-09
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From: |
Peter Maydell |
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Subject: |
Re: [PULL 00/17] NBD patches through 2021-03-09 |
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Date: |
Thu, 11 Mar 2021 20:40:59 +0000 |
On Thu, 11 Mar 2021 at 19:21, Eric Blake <eblake@redhat.com> wrote:
>
> On 3/11/21 1:02 PM, Peter Maydell wrote:
> > ERROR:../tests/test-cutils.c:2290:test_qemu_strtosz_metric: assertion
> > failed (res == 12345000): (12344999 == 12345000)
>
> Sounds like a floating point rounding error: the string was 12.345M, but
> 0.345 is not an exactly-representable double (the closest 32-bit IEEE
> 754 float is 0.3449999988079071044921875, while nextafter() gives
> 0.34500002861). Multiplying that value by 1000000.0 can then round down
> in some situations instead of producing the desired 345000.0. The
> rounding is less obvious with 64-bit doubles. I'm not sure why
> cross-i386-user seems to be prone to the rounding errors while other
> builds are not.
My guess would be x87 FPU vs SSE...
-- PMM
- [PULL 10/17] blockjob: return status from block_job_set_speed(), (continued)
- [PULL 10/17] blockjob: return status from block_job_set_speed(), Eric Blake, 2021/03/09
- [PULL 16/17] block/qed: bdrv_qed_do_open: deal with errp, Eric Blake, 2021/03/09
- [PULL 17/17] block/qcow2: refactor qcow2_update_options_prepare error paths, Eric Blake, 2021/03/09
- [PULL 08/17] block: drop extra error propagation for bdrv_set_backing_hd, Eric Blake, 2021/03/09
- [PULL 14/17] block/qcow2: read_cache_sizes: return status value, Eric Blake, 2021/03/09
- [PULL 09/17] block/mirror: drop extra error propagation in commit_active_start(), Eric Blake, 2021/03/09
- [PULL 15/17] block/qcow2: simplify qcow2_co_invalidate_cache(), Eric Blake, 2021/03/09
- Re: [PULL 00/17] NBD patches through 2021-03-09, Peter Maydell, 2021/03/11
- Re: [PULL 00/17] NBD patches through 2021-03-09, Peter Maydell, 2021/03/11