From: Philippe Proulx via lttng-dev <email@example.com> To: RADERMACHER Ansgar <Ansgar.RADERMACHER@cea.fr> Cc: "firstname.lastname@example.org" <email@example.com> Subject: Re: [lttng-dev] [barectf] How to ensure that last events before a crash get recorded Date: Fri, 5 Mar 2021 07:11:44 -0500 [thread overview] Message-ID: <CAB4xu_38oAbOD606ZQCp71oJ8qwYOt7F1Ssmpk=idhhTM7to6w@mail.gmail.com> (raw) In-Reply-To: <386C5D4D5C53C24CBC2C60CAAFD2136A5B4B2B92@EXDAG0-B1.intra.cea.fr> [-- Attachment #1.1: Type: text/plain, Size: 1480 bytes --] On Thu, Mar 4, 2021 at 10:28 RADERMACHER Ansgar via lttng-dev < firstname.lastname@example.org> wrote: > Hi, > > when doing tracing with barectf, the trace elements are written into a > buffer first and only written when the buffer is full - or if the function > barectf_platform_fs_fini gets called. > In case of a crash, it's therefore possible to loose some events. What is > the best option to prevent this issue? I've used signal handlers that call > the function barectf_platform_fs_fini. This seems to work well with Linux, > but is not portable. When using the provided sample platform, there is also > the option to reduce the buffer size, but this is not ideal, as trace > events that are too big for the buffer are not written. > First question: why are you using barectf on Linux vs LTTng? LTTng supports writing the sub-buffers to NVRAM and, if the system crashes, convert those sub-buffers to a CTF trace with the lttng-crash utility. See < https://lttng.org/docs/v2.12/#doc-persistent-memory-file-systems>. With NVRAM, you could do this with barectf with a corresponding platform using it. It's always up to the platform author to decide where buffers are and where complete packets go; it's not a feature of barectf as such. Hope it helps, Phil > Best regards > > Ansgar > > > _______________________________________________ > lttng-dev mailing list > email@example.com > https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev > -- Philippe Proulx [-- Attachment #1.2: Type: text/html, Size: 3234 bytes --] [-- Attachment #2: Type: text/plain, Size: 156 bytes --] _______________________________________________ lttng-dev mailing list firstname.lastname@example.org https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
next prev parent reply other threads:[~2021-03-05 12:12 UTC|newest] Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-03-04 15:06 RADERMACHER Ansgar via lttng-dev 2021-03-05 12:11 ` Philippe Proulx via lttng-dev [this message] 2021-03-05 12:27 ` RADERMACHER Ansgar via lttng-dev
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