{"id":42923293,"url":"https://github.com/fps/inter-process-wakeup-tests","last_synced_at":"2026-01-30T18:02:47.673Z","repository":{"id":239741643,"uuid":"800427696","full_name":"fps/inter-process-wakeup-tests","owner":"fps","description":"A collection of small test utilities to test different inter-process-wakeup mechanisms","archived":false,"fork":false,"pushed_at":"2024-05-17T07:41:03.000Z","size":38,"stargazers_count":0,"open_issues_count":0,"forks_count":0,"subscribers_count":1,"default_branch":"master","last_synced_at":"2024-05-17T16:19:50.741Z","etag":null,"topics":[],"latest_commit_sha":null,"homepage":null,"language":"C","has_issues":true,"has_wiki":null,"has_pages":null,"mirror_url":null,"source_name":null,"license":null,"status":null,"scm":"git","pull_requests_enabled":true,"icon_url":"https://github.com/fps.png","metadata":{"files":{"readme":"README.md","changelog":null,"contributing":null,"funding":null,"license":null,"code_of_conduct":null,"threat_model":null,"audit":null,"citation":null,"codeowners":null,"security":null,"support":null,"governance":null,"roadmap":null,"authors":null,"dei":null,"publiccode":null,"codemeta":null}},"created_at":"2024-05-14T10:10:22.000Z","updated_at":"2024-05-17T07:41:06.000Z","dependencies_parsed_at":"2024-05-14T11:44:54.769Z","dependency_job_id":null,"html_url":"https://github.com/fps/inter-process-wakeup-tests","commit_stats":null,"previous_names":["fps/inter-process-wakeup-tests"],"tags_count":0,"template":false,"template_full_name":null,"purl":"pkg:github/fps/inter-process-wakeup-tests","repository_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/fps%2Finter-process-wakeup-tests","tags_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/fps%2Finter-process-wakeup-tests/tags","releases_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/fps%2Finter-process-wakeup-tests/releases","manifests_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/fps%2Finter-process-wakeup-tests/manifests","owner_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners/fps","download_url":"https://codeload.github.com/fps/inter-process-wakeup-tests/tar.gz/refs/heads/master","sbom_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/fps%2Finter-process-wakeup-tests/sbom","scorecard":null,"host":{"name":"GitHub","url":"https://github.com","kind":"github","repositories_count":286080680,"owners_count":28917033,"icon_url":"https://github.com/github.png","version":null,"created_at":"2022-05-30T11:31:42.601Z","updated_at":"2026-01-30T16:37:38.804Z","status":"ssl_error","status_checked_at":"2026-01-30T16:37:37.878Z","response_time":66,"last_error":"SSL_connect returned=1 errno=0 peeraddr=140.82.121.5:443 state=error: unexpected eof while reading","robots_txt_status":"success","robots_txt_updated_at":"2025-07-24T06:49:26.215Z","robots_txt_url":"https://github.com/robots.txt","online":false,"can_crawl_api":true,"host_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub","repositories_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories","repository_names_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repository_names","owners_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners"}},"keywords":[],"created_at":"2026-01-30T18:02:45.958Z","updated_at":"2026-01-30T18:02:47.667Z","avatar_url":"https://github.com/fps.png","language":"C","funding_links":[],"categories":[],"sub_categories":[],"readme":"# Notes\n\n## General remarks\n\nFor some `i_`/`o-`/ pairs it is necessary for the `o_` program to be run first. For the others it doesn't matter, so if you run the `o_` program first in all cases it is always correct :)\n\n## Realtime scheduling\n\nDo not forget to use e.g. `chrt` to enable `SCHED_FIFO`. E.g.:\n\n```\nchrt -f 95 ./i_cond_shm \n```\n\n```\nchrt -f 95 ./o_cond_shm\n```\n\nAlso unless you have frequency scaling completely disabled it probably helps to run e.g. `stress -c \u003cnumber_of_threads_of_your_processor\u003e` to put load onto the system that forces it to the highest clock frequency.\n\n## Named pipes\n\nfor the `i_pipe` and `o_pipe` programs you need to create a named pipe with e.g.\n\n```\nmkfifo pipe\n```\n\nAnd then running\n\n```\nchrt -f 95 ./i_pipe pipe\n```\n\nand \n\n```\nchrt -f 95 ./o_pipe pipe\n```\n\n## Condition variable in shared memory\n\nYou have to run the `i_cond_shm` before `o_cond_shm` because the former initializes the mutex and condition variable in the shared memory.\n\n# Results\n\nHere are some example results..\n\n# AsRock N100DC-itx (Intel N100 CPU)\n\n```\nuname -a\nLinux ogfx100 6.6.30-rt30 #1-NixOS SMP PREEMPT_RT Thu May  2 14:32:50 UTC 2024 x86_64 GNU/Linux\n```\n\n## Named pipes\n\n## Condition variable in shared memory\n\n## Named semaphore\n\n## Unnamed semaphore\n\n## Spinning on a bare int in shared memory\n\n```\n./o_bare_int\nsecs: 284881, nsecs: 624681713\nsecs: 284882, nsecs: 624790675\nsecs: 284883, nsecs: 624922829\nsecs: 284884, nsecs: 625064580\nsecs: 284885, nsecs: 625205841\nsecs: 284886, nsecs: 625302734\nsecs: 284887, nsecs: 625440672\n^C\n```\n\n```\n[nix-shell:~/src/flow]$ ./i_bare_int\nsecs: 284881, nsecs: 624688671\nsecs: 284882, nsecs: 624791383\nsecs: 284883, nsecs: 624925238\nsecs: 284884, nsecs: 625065518\nsecs: 284885, nsecs: 625206521\nsecs: 284886, nsecs: 625303560\nsecs: 284887, nsecs: 625441486\n```\n\n0.8 us - that's more like it :)\n\n## Futex\n\n\n","project_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Ffps%2Finter-process-wakeup-tests","html_url":"https://awesome.ecosyste.ms/projects/github.com%2Ffps%2Finter-process-wakeup-tests","lists_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Ffps%2Finter-process-wakeup-tests/lists"}