Clojure

Improve slurp performance by using native Java StringWriter and jio/copy

Details

  • Type: Enhancement Enhancement
  • Status: Open Open
  • Priority: Major Major
  • Resolution: Unresolved
  • Affects Version/s: Release 1.3
  • Fix Version/s: None
  • Component/s: None
  • Labels:
  • Approval:
    Triaged

Description

Instead of copying each character from InputReader to StringBuffer.

Performance improvement:

From:
user> (time (count (slurp "/home/juergen/test.dat")))
"Elapsed time: 4269.980863 msecs"
104857600
To:
user> (time (count (slurp "/home/juergen/test.dat")))
"Elapsed time: 1140.854023 msecs"
104857600

Approach: Use StringWriter and jio/copy vs character by character copy. Results from the current patch see a 4-5x perf boost after the jit warms up, with purely in-memory streams (ByteArrayInputStream over a 6MB string).

Patch: slurp-perf-patch.diff

Activity

Hide
Alex Miller added a comment -

This is double-better with the changes in Clojure 1.6 to improve jio/copy performance by using the NIO impl. Rough timing difference on a 25M file: old= 2316.021 msecs, new= 93.319 msecs.

Filer did not supply a patch and is not a contributor. If someone wants to make a patch (and better timing info demonstrating performance improvements), that would be great.

Show
Alex Miller added a comment - This is double-better with the changes in Clojure 1.6 to improve jio/copy performance by using the NIO impl. Rough timing difference on a 25M file: old= 2316.021 msecs, new= 93.319 msecs. Filer did not supply a patch and is not a contributor. If someone wants to make a patch (and better timing info demonstrating performance improvements), that would be great.
Hide
Timothy Baldridge added a comment -

Fixed the ticket formatting a bit, and added a patch I coded up tonight. Should be pretty close to the old patch, as we both use StringWriter, but I didn't really look at the old patch beyond noticing that it was using StringWriter.

Show
Timothy Baldridge added a comment - Fixed the ticket formatting a bit, and added a patch I coded up tonight. Should be pretty close to the old patch, as we both use StringWriter, but I didn't really look at the old patch beyond noticing that it was using StringWriter.
Hide
Alex Miller added a comment -

Can you update the perf comparison on latest code and do both a small and big file?

Show
Alex Miller added a comment - Can you update the perf comparison on latest code and do both a small and big file?

People

Vote (0)
Watch (1)

Dates

  • Created:
    Updated: