> Add the Base64 Decode intrinsic for x86 to utilize AVX-512 for acceleration. > Also allows for performance improvement for non-AVX-512 enabled platforms. > Due to the nature of MIME-encoded inputs, modify the intrinsic signature to > accept an additional parameter (isMIME) for fast-path MIME decoding. > > A change was made to the signature of DecodeBlock in Base64.java to provide > the intrinsic information as to whether MIME decoding was being done. This > allows for the intrinsic to bypass the expensive setup of zmm registers from > AVX tables, knowing there may be invalid Base64 characters every 76 > characters or so. A change was also made here removing the restriction that > the intrinsic must return an even multiple of 3 bytes decoded. This > implementation handles the pad characters at the end of the string and will > return the actual number of characters decoded. > > The AVX portion of this code will decode in blocks of 256 bytes per loop > iteration, then in chunks of 64 bytes, followed by end fixup decoding. The > non-AVX code is an assembly-optimized version of the java DecodeBlock and > behaves identically. > > Running the Base64Decode benchmark, this change increases decode performance > by an average of 2.6x with a maximum 19.7x for buffers > ~20k. The numbers > are given in the table below. > > **Base Score** is without intrinsic support, **Optimized Score** is using > this intrinsic, and **Gain** is **Base** / **Optimized**. > > > Benchmark Name | Base Score | Optimized Score | Gain > -- | -- | -- | -- > testBase64Decode size 1 | 15.36 | 15.32 | 1.00 > testBase64Decode size 3 | 17.00 | 16.72 | 1.02 > testBase64Decode size 7 | 20.60 | 18.82 | 1.09 > testBase64Decode size 32 | 34.21 | 26.77 | 1.28 > testBase64Decode size 64 | 54.43 | 38.35 | 1.42 > testBase64Decode size 80 | 66.40 | 48.34 | 1.37 > testBase64Decode size 96 | 73.16 | 52.90 | 1.38 > testBase64Decode size 112 | 84.93 | 51.82 | 1.64 > testBase64Decode size 512 | 288.81 | 32.04 | 9.01 > testBase64Decode size 1000 | 560.48 | 40.79 | 13.74 > testBase64Decode size 20000 | 9530.28 | 483.37 | 19.72 > testBase64Decode size 50000 | 24552.24 | 1735.07 | 14.15 > testBase64MIMEDecode size 1 | 22.87 | 21.36 | 1.07 > testBase64MIMEDecode size 3 | 27.79 | 25.32 | 1.10 > testBase64MIMEDecode size 7 | 44.74 | 43.81 | 1.02 > testBase64MIMEDecode size 32 | 142.69 | 129.56 | 1.10 > testBase64MIMEDecode size 64 | 256.90 | 243.80 | 1.05 > testBase64MIMEDecode size 80 | 311.60 | 310.80 | 1.00 > testBase64MIMEDecode size 96 | 364.00 | 346.66 | 1.05 > testBase64MIMEDecode size 112 | 472.88 | 394.78 | 1.20 > testBase64MIMEDecode size 512 | 1814.96 | 1671.28 | 1.09 > testBase64MIMEDecode size 1000 | 3623.50 | 3227.61 | 1.12 > testBase64MIMEDecode size 20000 | 70484.09 | 64940.77 | 1.09 > testBase64MIMEDecode size 50000 | 191732.34 | 158158.95 | 1.21 > testBase64WithErrorInputsDecode size 1 | 1531.02 | 1185.19 | 1.29 > testBase64WithErrorInputsDecode size 3 | 1306.59 | 1170.99 | 1.12 > testBase64WithErrorInputsDecode size 7 | 1238.11 | 1176.62 | 1.05 > testBase64WithErrorInputsDecode size 32 | 1346.46 | 1138.47 | 1.18 > testBase64WithErrorInputsDecode size 64 | 1195.28 | 1172.52 | 1.02 > testBase64WithErrorInputsDecode size 80 | 1469.00 | 1180.94 | 1.24 > testBase64WithErrorInputsDecode size 96 | 1434.48 | 1167.74 | 1.23 > testBase64WithErrorInputsDecode size 112 | 1440.06 | 1162.56 | 1.24 > testBase64WithErrorInputsDecode size 512 | 1362.79 | 1193.42 | 1.14 > testBase64WithErrorInputsDecode size 1000 | 1426.07 | 1194.44 | 1.19 > testBase64WithErrorInputsDecode size 20000 | 1398.44 | 1138.17 | 1.23 > testBase64WithErrorInputsDecode size 50000 | 1409.41 | 1114.16 | 1.26
Scott Gibbons has updated the pull request incrementally with one additional commit since the last revision: Addressing review comments. 1. Changed errorvec handling 2. Removed unnecessary register copies and aliasing 3. Streamlined mask generation ------------- Changes: - all: https://git.openjdk.java.net/jdk/pull/4368/files - new: https://git.openjdk.java.net/jdk/pull/4368/files/bb73df6c..e1b4af9e Webrevs: - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=4368&range=05 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=4368&range=04-05 Stats: 55 lines in 1 file changed: 0 ins; 29 del; 26 mod Patch: https://git.openjdk.java.net/jdk/pull/4368.diff Fetch: git fetch https://git.openjdk.java.net/jdk pull/4368/head:pull/4368 PR: https://git.openjdk.java.net/jdk/pull/4368
