It seems the perf step of the GTK perf bot is timing out https://build.webkit.org/builders/GTK%20Linux%2064-bit%20Release%20%28Perf%29 therefore is not uploading data :(
On bug 203083 I skipped the test that was timing out. But maybe others time out after that. I think we need to modify how this step runs so there is a per-test timeout that is lower than the whole step timeout-without-output, to ensure the step always finishes (even when there are test timeouts) I will try to upload a patch for that here.