Opened 4 years ago

Last modified 14 months ago

#21253 needs_revision task

Add link handshakes to benchmark program

Reported by: nickm Owned by:
Priority: High Milestone: Tor: unspecified
Component: Core Tor/Tor Version:
Severity: Normal Keywords: triaged-out-20170124 performance testing link-handshake
Cc: Actual Points: 1
Parent ID: Points: 1
Reviewer: Sponsor: SponsorU-must


Our ed25519 handshake may have slowed link handshakes down a little. How much? We should add a couple of items to ./src/test/bench

This is follow-on item for sponsor U, prop220, and #15055.

Child Tickets

Change History (8)

comment:1 Changed 4 years ago by nickm

Owner: set to nickm
Status: newaccepted

comment:2 Changed 4 years ago by nickm

work-in-progress branch in linkbench: done by kludging the unit test code, for fast results.

TLS link handshake:

  • The biggest slowdown here comes from moving from 1024-bit RSA keys to 2048-bit RSA keys on our TLS connections: this represents a 7x slowdown on the server side. We should consider moving to ECDSA link certificates if they're used enough to make us not stand out. This is the biggest additional cost in our new handshake.

In-tor link handshake:

  • There appear to be no significant server-side slowdowns on the client->server link authentication stage.
  • The client side of the client->server link authentication stage is about 2x slower, but shouldn't matter for actual performance;
  • The server->server link authentication is slower than before by about the cost of a two ntor handshakes. Caching certificate validity info could help here.

comment:3 Changed 4 years ago by nickm

Keywords: triaged-out-20170124 added
Milestone: Tor: 0.3.0.x-finalTor: 0.3.1.x-final

comment:4 Changed 3 years ago by nickm

Actual Points: 1
Milestone: Tor: 0.3.1.x-finalTor: unspecified
Points: 1
Status: acceptedneeds_review

Actually merging this would be pretty nontrivial; it needs more work to be "good enough"

comment:5 Changed 3 years ago by nickm

Status: needs_reviewneeds_revision

comment:6 Changed 3 years ago by nickm

Keywords: performance testing link-handshake added

comment:7 Changed 14 months ago by nickm

Owner: nickm deleted
Status: needs_revisionassigned

comment:8 Changed 14 months ago by nickm

Status: assignedneeds_revision

None of these revisions are in my near-term plans.

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