{"action":"created","issue":{"url":"https://api.github.com/repos/01org/processor-trace/issues/39","repository_url":"https://api.github.com/repos/01org/processor-trace","labels_url":"https://api.github.com/repos/01org/processor-trace/issues/39/labels{/name}","comments_url":"https://api.github.com/repos/01org/processor-trace/issues/39/comments","events_url":"https://api.github.com/repos/01org/processor-trace/issues/39/events","html_url":"https://github.com/01org/processor-trace/issues/39","id":314672890,"number":39,"title":"error: expected tracing enabled event","user":{"login":"vext01","id":604955,"avatar_url":"https://avatars2.githubusercontent.com/u/604955?v=4","gravatar_id":"","url":"https://api.github.com/users/vext01","html_url":"https://github.com/vext01","followers_url":"https://api.github.com/users/vext01/followers","following_url":"https://api.github.com/users/vext01/following{/other_user}","gists_url":"https://api.github.com/users/vext01/gists{/gist_id}","starred_url":"https://api.github.com/users/vext01/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/vext01/subscriptions","organizations_url":"https://api.github.com/users/vext01/orgs","repos_url":"https://api.github.com/users/vext01/repos","events_url":"https://api.github.com/users/vext01/events{/privacy}","received_events_url":"https://api.github.com/users/vext01/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"assignees":[],"milestone":null,"comments":7,"created_at":"2018-04-16T14:21:57Z","updated_at":"2018-04-18T12:00:36Z","closed_at":null,"author_association":"CONTRIBUTOR","body":"Hello!\r\n\r\nI've noticed that when I trace user code (using `attr.exclude_kernel = 1`) and there's a system call in the trace, then ptxed will generate en error message upon returning to user-space:\r\n```                                              \r\n$ ptxed --cpu auto, --block-decoder --block:end-on-call --block:end-on-jump \\\r\n            --block:show-blocks --pt ...\r\n...\r\n0000557a22886c5c  mov edi, dword ptr [rdi+0x18]         \r\n0000557a22886c5f  call 0x557a22878f58         \r\n[block]         \r\n0000557a22878f58  jmp qword ptr [rip+0x2f1c7a]         \r\n[block]         \r\n00007fde76ddfe00  mov eax, 0x10         \r\n00007fde76ddfe05  syscall          \r\n[disabled]         \r\n[3ec80, 7fde76ddfe07: error: expected tracing enabled event]         <--------- this\r\n[block]         \r\n00007ffe85dc5a20  jle 0x7ffe85dc5b1d         \r\n[block]         \r\n```\r\n\r\nIs that supposed to happen? If not, I'm wondering if that's a bug in `ptxed`, the Linux kernel I'm using (`4.9.30-2+deb9u5`), or the chip itself?\r\n\r\nAny ideas?"},"comment":{"url":"https://api.github.com/repos/01org/processor-trace/issues/comments/382362596","html_url":"https://github.com/01org/processor-trace/issues/39#issuecomment-382362596","issue_url":"https://api.github.com/repos/01org/processor-trace/issues/39","id":382362596,"user":{"login":"markus-metzger","id":5424725,"avatar_url":"https://avatars2.githubusercontent.com/u/5424725?v=4","gravatar_id":"","url":"https://api.github.com/users/markus-metzger","html_url":"https://github.com/markus-metzger","followers_url":"https://api.github.com/users/markus-metzger/followers","following_url":"https://api.github.com/users/markus-metzger/following{/other_user}","gists_url":"https://api.github.com/users/markus-metzger/gists{/gist_id}","starred_url":"https://api.github.com/users/markus-metzger/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/markus-metzger/subscriptions","organizations_url":"https://api.github.com/users/markus-metzger/orgs","repos_url":"https://api.github.com/users/markus-metzger/repos","events_url":"https://api.github.com/users/markus-metzger/events{/privacy}","received_events_url":"https://api.github.com/users/markus-metzger/received_events","type":"User","site_admin":false},"created_at":"2018-04-18T12:00:36Z","updated_at":"2018-04-18T12:00:36Z","author_association":"CONTRIBUTOR","body":"Hello Edd,\r\n\r\nthe VDSO does the syscall.\r\n\r\nSo it is working fine also with the syscall as long as the trace is short enough.  Maybe short enough to not wrap around the AUX buffer?\r\n\r\nI would still expect some collection error either due to overwrites, truncates, or bad stitching of the trace pieces.\r\n\r\nThe syscall gives a moment of rest where tracing is temporarily disabled.  Maybe that's why you're seeing this always after a syscall.  You could try replacing it with a simple volatile variable increment or some other trivial code and increase iters to compensate.\r\n\r\nYou could also try recording your sample application with perf to get a second opinion from another tool.\r\n\r\nregards,\r\nmarkus."}}
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