RFR: 6478546: FileInputStream.read() throws OutOfMemoryError when there is plenty available [v5]

[Brian Burkhalter]

On Thu, 9 Jun 2022 18:38:18 GMT, Brian Burkhalter <bpb at openjdk.org> wrote:

>> Modify native multi-byte read-write code used by the `java.io` classes to limit the size of the allocated native buffer thereby decreasing off-heap memory footprint and increasing throughput.
>
> Brian Burkhalter has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains seven additional commits since the last revision:
> 
>  - Merge
>  - 6478546: Add break in write loop on ExceptionOccurred
>  - Merge
>  - 6478546: Clean up io_util.c
>  - Merge
>  - 6478546: Decrease malloc'ed buffer maximum size to 64 kB
>  - 6478546: FileInputStream.read() throws OutOfMemoryError when there is plenty available

The following benchmark results are for commit e6f3b4574b1c49955e5acaca618a3083eb132e05 with 5 warmup iterations of 5 seconds each, followed by 10 measurement iterations of 10 seconds each on a MacBookPro16,1.

           FileInputStream.read(byte[])

                   Score (ops/s)
(length)       Master              Branch
16384      5850.383 ± 220.209  5805.952 ± 187.870
32768      5781.410 ± 345.939  5807.587 ± 515.808
100000     5444.167 ± 409.680  5273.988 ± 159.652
500000     3748.413 ±  88.505  3803.577 ± 256.442
1000000    2647.356 ± 145.245  2700.523 ±  97.717
1048576    2759.337 ± 362.618  2631.779 ±  45.971
10485760    338.840 ±   2.706   392.126 ±   2.59
251503002    10.626 ±   0.024    20.165 ±   0.091
524288000     5.134 ±   0.024     9.826 ±   0.068
1000000000    1.806 ±   0.014     5.194 ±   0.015

           FileOutputStream.write(byte[])

                   Score (ops/s)
(length)       Master              Branch
16384      2736.489 ±  31.547  2599.203 ±  79.392
32768      2656.471 ±  72.597  2523.470 ± 158.460
100000     2476.514 ±  46.392  2225.597 ± 442.285
500000     1606.205 ± 487.787  1281.550 ± 413.797
1000000    1125.265 ±  13.969   812.184 ± 232.23
1048576    1098.608 ±  13.528   816.657 ± 218.112
10485760    136.867 ±   2.310   153.137 ±   2.93
251503002     7.266 ±   0.026    10.546 ±   0.125
524288000     3.450 ±   0.016     3.880 ±   1.355
1000000000    1.178 ±   0.007     2.637 ±   0.505


The proposed change is approximately at parity with the current code base for smaller lengths, but has higher throughput for larger lengths, at least for reading. In all cases where the length is greater than or equal to 65536 (64 KiB) or is a multiple of 8192 (8 KiB), less native memory is allocated.

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PR: https://git.openjdk.org/jdk/pull/8235