public inbox for gcc-bugs@sourceware.org help / color / mirror / Atom feed
From: "rdiezmail-gcc at yahoo dot de" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug other/94330] New: No warning if jobserver not available Date: Wed, 25 Mar 2020 15:34:49 +0000 [thread overview] Message-ID: <bug-94330-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94330 Bug ID: 94330 Summary: No warning if jobserver not available Product: gcc Version: 8.3.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: other Assignee: unassigned at gcc dot gnu.org Reporter: rdiezmail-gcc at yahoo dot de Target Milestone: --- If you pass -flto=jobserver , and the jobserver file descriptors are not actually available, you get no warning whatsoever from GCC. GNU Make does try to help in this scenario with the following warning: make[1]: warning: jobserver unavailable: using -j1. Add `+' to parent make rule. Without such a warning, it is really easy to miss the opportunity to parallelise the build. In fact, GCC seems to use 2 threads in this scenario, which misleads you into thinking that the option is working correctly, when in fact is not using all other CPU cores. More context on this issue is here: https://lists.gnu.org/archive/html/help-make/2020-02/msg00000.html https://gcc.gnu.org/legacy-ml/gcc-help/2020-02/msg00069.html
next reply other threads:[~2020-03-25 15:34 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-03-25 15:34 rdiezmail-gcc at yahoo dot de [this message] 2020-03-26 6:55 ` [Bug driver/94330] " rguenth at gcc dot gnu.org 2020-03-26 9:00 ` marxin at gcc dot gnu.org 2020-03-26 9:41 ` marxin at gcc dot gnu.org 2020-05-05 14:11 ` cvs-commit at gcc dot gnu.org 2020-05-05 14:13 ` marxin at gcc dot gnu.org
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=bug-94330-4@http.gcc.gnu.org/bugzilla/ \ --to=gcc-bugzilla@gcc.gnu.org \ --cc=gcc-bugs@gcc.gnu.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).