server: optimize BCE on the packetio.writePacket

[hawkingrei]

Signed-off-by: Weizhen Wang wangweizhen@pingcap.com

What problem does this PR solve?

Go is a memory safe language. In array/slice element indexing and subslice operations, Go runtime will check whether or not the involved indexes are out of range. If an index is out of range, a panic will be produced to prevent the invalid index from doing harm. This is called bounds check. Bounds checks make our code run safely, on the other hand, they also make our code run a little slower.

Issue Number: ref #34669

Problem Summary:

What is changed and how it works?

before

goos: darwin
goarch: amd64
pkg: github.com/pingcap/tidb/server
cpu: Intel(R) Core(TM) i9-9880H CPU @ 2.30GHz
BenchmarkPacketIOWrite-16    	10000000	       871.3 ns/op
PASS
ok  	github.com/pingcap/tidb/server	9.875s

after

goos: darwin
goarch: amd64
pkg: github.com/pingcap/tidb/server
cpu: Intel(R) Core(TM) i9-9880H CPU @ 2.30GHz
BenchmarkPacketIOWrite-16    	10000000	       830.0 ns/op
PASS
ok  	github.com/pingcap/tidb/server	9.102s

4% performance improvement.

BTW, the performance gain increases as the data size increases.

Check List

Tests

• Unit test
• Integration test

Release note

Please refer to Release Notes Language Style Guide to write a quality release note.

None

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• bb7133
• tiancaiamao

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[sre-bot]

Code Coverage Details: https://codecov.io/github/pingcap/tidb/commit/da12937ada2a0ef7b9998f77c4f85b81e261e3e6

[bb7133]

LGTM

[tiancaiamao]

/merge

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: 116720f

[hawkingrei]

/run-mysql-test

[sre-bot]

TiDB MergeCI notify

🔴 Bad News! New failing [1] after this pr merged.
These new failed integration tests seem to be caused by the current PR, please try to fix these new failed integration tests, thanks!

CI Name	Result	Duration	Compare with Parent commit
idc-jenkins-ci-tidb/integration-ddl-test	🟥 failed 1, success 5, total 6	13 min	New failing
idc-jenkins-ci/integration-cdc-test	🟢 all 34 tests passed	23 min	Existing passed
idc-jenkins-ci-tidb/integration-common-test	🟢 all 11 tests passed	13 min	Existing passed
idc-jenkins-ci-tidb/sqllogic-test-1	🟢 all 26 tests passed	7 min 10 sec	Existing passed
idc-jenkins-ci-tidb/common-test	🟢 all 12 tests passed	6 min 46 sec	Existing passed
idc-jenkins-ci-tidb/sqllogic-test-2	🟢 all 28 tests passed	6 min 25 sec	Existing passed
idc-jenkins-ci-tidb/tics-test	🟢 all 1 tests passed	6 min 19 sec	Existing passed
idc-jenkins-ci-tidb/mybatis-test	🟢 all 1 tests passed	4 min 33 sec	Existing passed
idc-jenkins-ci-tidb/integration-compatibility-test	🟢 all 1 tests passed	3 min 28 sec	Existing passed
idc-jenkins-ci-tidb/plugin-test	🟢 build success, plugin test success	4min	Existing passed