github/jgit - jgit - 帆软第三方插件仓库

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Author	SHA1	Message	Date
Matthias Sohn	5911521ba6	Measure minimum racy interval to auto-configure FileSnapshot By running FileSnapshotTest#detectFileModified we found that the sum of measured filesystem timestamp resolution and measured clock resolution may yield a too small interval after a file has been modified which we need to consider racily clean. In our tests we didn't find this behavior on all systems we tested on, e.g. on MacOS using APFS and Java 8 and 11 this effect was not observed. On Linux (SLES 15, kernel 4.12.14-150.22-default) we collected the following test results using Java 8 and 11: In 23-98% of 10000 test runs (depending on filesystem type and Java version) the test failed, which means the effective interval which needs to be considered racily clean after a file was modified is larger than the measured file timestamp resolution. "delta" is the observed interval after a file has been modified but FileSnapshot did not yet detect the modification: "resolution" is the measured sum of file timestamp resolution and clock resolution seen in Java. Java version filesystem failures resolution min delta max delta 1.8.0_212-b04 btrfs 98.6% 1 ms 3.6 ms 6.6 ms 1.8.0_212-b04 ext4 82.6% 3 ms 1.1 ms 4.1 ms 1.8.0_212-b04 xfs 23.8% 4 ms 3.7 ms 3.9 ms 1.8.0_212-b04 zfs 23.1% 3 ms 4.8 ms 5.0 ms 11.0.3+7 btrfs 98.1% 3 us 0.7 ms 4.7 ms 11.0.3+7 ext4 98.1% 6 us 0.7 ms 4.7 ms 11.0.3+7 xfs 98.5% 7 us 0.1 ms 8.0 ms 11.0.3+7 zfs 98.4% 7 us 0.7 ms 5.2 ms Mac OS 1.8.0_212 APFS 0% 1 s 11.0.3+7 APFS 0% 6 us The observed delta is not distributed according to a normal gaussian distribution but rather random in the observed range between "min delta" and "max delta". Run this test after measuring file timestamp resolution in FS.FileAttributeCache to auto-configure JGit since it's unclear what mechanism is causing this effect. In FileSnapshot#isRacyClean use the maximum of the measured timestamp resolution and the measured "delta" as explained above to decide if a given FileSnapshot is to be considered racily clean. Add a 30% safety margin to ensure we are on the safe side. Change-Id: I1c8bb59f6486f174b7bbdc63072777ddbe06694d Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>	5 years ago
Matthias Sohn	09fec1a102	Add debug trace for FileSnapshot Checking lastModified is time critical hence debug trace is the only way to analyze issues since debugging is impractical. Also add configuration for buffering of log4j output to reduce runtime impact when debug trace is on. Limit buffer to 1MiB and comment this configuration out since we may not always want to use buffering. Change-Id: Ib1a0537b67c8dc3fac994a77b42badd974ce6c97 Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>	5 years ago
Andrei Pozolotin	81810aff29	Adding AES Walk Encryption support in http://www.jets3t.org/ mode See previous attempt: https://git.eclipse.org/r/#/c/16674/ Here we preserve as much of JetS3t mode as possible while allowing to use new Java 8+ PBE algorithms such as PBEWithHmacSHA512AndAES_256 Summary of changes: * change pom.xml to control long tests * add WalkEncryptionTest.launch to run long tests * add AmazonS3.Keys to to normalize use of constants * change WalkEncryption to support AES in JetS3t mode * add WalkEncryptionTest to test remote encryption pipeline * add support for CI configuration for live Amazon S3 testing * add log4j based logging for tests in both Eclipse and Maven build To test locally, check out the review branch, then: * create amazon test configuration file * located your home dir: ${user.home} * named jgit-s3-config.properties * file format follows AmazonS3 connection settings file: accesskey = your-amazon-access-key secretkey = your-amazon-secret-key test.bucket = your-bucket-for-testing * finally: * run in Eclipse: WalkEncryptionTest.launch * or * run in Shell: mvn test --define test=WalkEncryptionTest Change-Id: I6f455fd9fb4eac261ca73d0bec6a4e7dae9f2e91 Signed-off-by: Andrei Pozolotin <andrei.pozolotin@gmail.com>	9 years ago

Author

SHA1

Message

Date

Matthias Sohn

5911521ba6

Measure minimum racy interval to auto-configure FileSnapshot

By running FileSnapshotTest#detectFileModified we found that the sum of
measured filesystem timestamp resolution and measured clock resolution
may yield a too small interval after a file has been modified which we
need to consider racily clean. In our tests we didn't find this behavior
on all systems we tested on, e.g. on MacOS using APFS and Java 8 and 11
this effect was not observed.

On Linux (SLES 15, kernel 4.12.14-150.22-default) we collected the
following test results using Java 8 and 11:

In 23-98% of 10000 test runs (depending on filesystem type and Java
version) the test failed, which means the effective interval which needs
to be considered racily clean after a file was modified is larger than
the measured file timestamp resolution.

"delta" is the observed interval after a file has been modified but
FileSnapshot did not yet detect the modification:

"resolution" is the measured sum of file timestamp resolution and clock
resolution seen in Java.

Java version    filesystem  failures resolution  min delta   max delta
1.8.0_212-b04   btrfs	    98.6%       1 ms        3.6 ms      6.6 ms
1.8.0_212-b04   ext4        82.6%       3 ms        1.1 ms      4.1 ms
1.8.0_212-b04   xfs         23.8%       4 ms        3.7 ms      3.9 ms
1.8.0_212-b04   zfs         23.1%       3 ms        4.8 ms      5.0 ms
11.0.3+7        btrfs       98.1%       3 us        0.7 ms      4.7 ms
11.0.3+7        ext4        98.1%       6 us        0.7 ms      4.7 ms
11.0.3+7        xfs         98.5%       7 us        0.1 ms      8.0 ms
11.0.3+7        zfs         98.4%       7 us        0.7 ms      5.2 ms

Mac OS
1.8.0_212       APFS        0%          1 s
11.0.3+7        APFS        0%          6 us

The observed delta is not distributed according to a normal gaussian
distribution but rather random in the observed range between "min delta"
and "max delta".

Run this test after measuring file timestamp resolution in
FS.FileAttributeCache to auto-configure JGit since it's unclear what
mechanism is causing this effect.

In FileSnapshot#isRacyClean use the maximum of the measured timestamp
resolution and the measured "delta" as explained above to decide if a
given FileSnapshot is to be considered racily clean. Add a 30% safety
margin to ensure we are on the safe side.

Change-Id: I1c8bb59f6486f174b7bbdc63072777ddbe06694d
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

5 years ago

Matthias Sohn

09fec1a102

Add debug trace for FileSnapshot

Checking lastModified is time critical hence debug trace is the only way
to analyze issues since debugging is impractical.

Also add configuration for buffering of log4j output to reduce runtime
impact when debug trace is on. Limit buffer to 1MiB and comment this
configuration out since we may not always want to use buffering.

Change-Id: Ib1a0537b67c8dc3fac994a77b42badd974ce6c97
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

5 years ago

Andrei Pozolotin

81810aff29

Adding AES Walk Encryption support in http://www.jets3t.org/ mode

See previous attempt: https://git.eclipse.org/r/#/c/16674/

Here we preserve as much of JetS3t mode as possible
while allowing to use new Java 8+ PBE algorithms
such as PBEWithHmacSHA512AndAES_256

Summary of changes:
* change pom.xml to control long tests
* add WalkEncryptionTest.launch to run long tests
* add AmazonS3.Keys to to normalize use of constants
* change WalkEncryption to support AES in JetS3t mode
* add WalkEncryptionTest to test remote encryption pipeline
* add support for CI configuration for live Amazon S3 testing
* add log4j based logging for tests in both Eclipse and Maven build

To test locally, check out the review branch, then:
* create amazon test configuration file
* located your home dir: ${user.home}
* named jgit-s3-config.properties
* file format follows AmazonS3 connection settings file:
	accesskey = your-amazon-access-key
	secretkey = your-amazon-secret-key
	test.bucket = your-bucket-for-testing
* finally:
* run in Eclipse: WalkEncryptionTest.launch
* or
* run in Shell: mvn test --define test=WalkEncryptionTest

Change-Id: I6f455fd9fb4eac261ca73d0bec6a4e7dae9f2e91
Signed-off-by: Andrei Pozolotin <andrei.pozolotin@gmail.com>

9 years ago

3 Commits (42000a71e3b73639f8ba2858f8ba8e7941a1ab1c)