[I] TestDirectIODirectory is slow [lucene]

[via GitHub]

dweiss opened a new issue, #14315:
URL: https://github.com/apache/lucene/issues/14315

   ### Description
   
   Something is odd here.  This, on main:
   
   ```
   ./gradlew :lucene:misc:test --tests 
"org.apache.lucene.misc.store.TestDirectIODirectory" -Ptests.jvms=4 
-Ptests.jvmargs= -Ptests.seed=DEE483D0402DBE52 -Ptests.multiplier=2 
-Ptests.useSecurityManager=true -Ptests.nightly=true -Ptests.vectorsize=512 
-Ptests.forceintegervectors=true
   ```
   
   Takes a veeery long time. Specifically, testRandomByte from the parent class 
(BaseDirectoryTestCase) takes ages, with this loop:
   ```
         // subslices
         for (int offset = 1; offset < bytes.length; offset++) {
           RandomAccessInput subslice = input.randomAccessSlice(offset, 
input.length() - offset);
           assertEquals(input.length() - offset, subslice.length());
           assertBytes(subslice, bytes, offset);
         }
   ```
   taking the most of the time. The slices involved are not large. But here's a 
sample flame graph from the profiler on Linux -
   
   
![Image](https://github.com/user-attachments/assets/1aed6636-5894-43a0-a0cb-1cb318d97f26)
   
   Seems like those native pread0 reads are where it's spending most of the 
time... I didn't have time to compare to a different system yet (or measure it 
more accurately deeper into the native stack).
   
   ### Version and environment details
   
   _No response_


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