Fix benchmark problem

[VoVAllen]

Description

Checklist

Please feel free to remove inapplicable items for your PR.

• The PR title starts with [$CATEGORY] (such as [NN], [Model], [Doc], [Feature]])
• Changes are complete (i.e. I finished coding on this PR)
• All changes have test coverage
• Code is well-documented
• To the best of my knowledge, examples are either not affected by this change,
  or have been fixed to be compatible with this change
• Related issue is referred in this PR
• If the PR is for a new model/paper, I've updated the example index here.

Changes

[dgl-bot]

To trigger regression tests:

• @dgl-bot run [instance-type] [which tests] [compare-with-branch];
  For example: @dgl-bot run g4dn.4xlarge all dmlc/master or @dgl-bot run c5.9xlarge kernel,api dmlc/master

[VoVAllen]

@dgl-bot run r6i.16xlarge model_speed dmlc/0.7.x

[dgl-bot]

Start the Regression test. View at https://ci.dgl.ai/job/dgl/job/PR-3762/3/display/redirect

[dgl-bot]

Finished the Regression test. Result table is at https://dgl-asv-data.s3-us-west-2.amazonaws.com/68930b20572051100103ca5deeb2ceff101ba40d_r6i16xlarge/results/result.csv. Jenkins job link is https://ci.dgl.ai/job/dgl/job/PR-3762/3/display/redirect.

[VoVAllen]

@dgl-bot run r6i.16xlarge model_speed dmlc/0.7.x

[dgl-bot]

Start the Regression test. View at https://ci.dgl.ai/job/dgl/job/PR-3762/5/display/redirect

[dgl-bot]

Finished the Regression test. Result table is at https://dgl-asv-data.s3-us-west-2.amazonaws.com/0b8a840768809f029af4264f68a043208d738ed4_r6i16xlarge/results/result.csv. Jenkins job link is https://ci.dgl.ai/job/dgl/job/PR-3762/5/display/redirect.

[VoVAllen]

@dgl-bot run r6i.16xlarge model_speed dmlc/0.7.x

[dgl-bot]

Start the Regression test. View at https://ci.dgl.ai/job/dgl/job/PR-3762/9/display/redirect

[dgl-bot]

Finished the Regression test. Result table is at https://dgl-asv-data.s3-us-west-2.amazonaws.com/d53be6e4f66938676c76126d27a077a1258fcf05_r6i16xlarge/results/result.csv. Jenkins job link is https://ci.dgl.ai/job/dgl/job/PR-3762/9/display/redirect.

[VoVAllen]

@dgl-bot run r6i.16xlarge model_speed dmlc/0.7.x

[dgl-bot]

Start the Regression test. View at https://ci.dgl.ai/job/dgl/job/PR-3762/11/display/redirect

[VoVAllen]

@dgl-bot run r6i.16xlarge model_speed dmlc/0.7.x

[dgl-bot]

Start the Regression test. View at https://ci.dgl.ai/job/dgl/job/PR-3762/12/display/redirect

[VoVAllen]

@dgl-bot run r6i.16xlarge model_speed dmlc/0.7.x

[dgl-bot]

Start the Regression test. View at https://ci.dgl.ai/job/dgl/job/PR-3762/14/display/redirect

[VoVAllen]

@dgl-bot run r6i.16xlarge model_speed dmlc/0.7.x

[dgl-bot]

Start the Regression test. View at https://ci.dgl.ai/job/dgl/job/PR-3762/16/display/redirect

[dgl-bot]

Finished the Regression test. Result table is at https://dgl-asv-data.s3-us-west-2.amazonaws.com/0cf1c2fb05bd682b99be12be498c1da215c0f7ad_r6i16xlarge/results/result.csv. Jenkins job link is https://ci.dgl.ai/job/dgl/job/PR-3762/16/display/redirect.