From: Peter Zijlstra <peterz@infradead.org>
To: Julien Desfossez <jdesfossez@efficios.com>
Cc: tglx@linutronix.de, rostedt@goodmis.org, mingo@redhat.com,
daolivei@redhat.com, mathieu.desnoyers@efficios.com,
linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH v2 0/5] Additional scheduling information in tracepoints
Date: Mon, 26 Sep 2016 14:27:12 +0200 [thread overview]
Message-ID: <20160926122712.GM5012@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <1474649375-28056-1-git-send-email-jdesfossez@efficios.com>
On Fri, Sep 23, 2016 at 12:49:30PM -0400, Julien Desfossez wrote:
> With this macro, we propose new versions of the sched_switch, sched_waking,
> sched_process_fork and sched_pi_setprio tracepoint probes that contain more
> scheduling information and get rid of the "prio" field. We also add the PI
> information to these tracepoints, so if a process is currently boosted, we show
> the name and PID of the top waiter. This allows to quickly see the blocking
> chain even if some of the trace background is missing.
Urgh.. bigger mess than ever :-(
So I thought the initial idea was to provide a 'blocked-on' tracepoint,
along with with the 'prio-changed' tracepoint, so you can reconstruct
the entire PI chain.
The only problem with that was initial state; when you start tracing (or
miss the start of a trace) its hard (impossible) to know what the
current state is.
But now you send a patch-set that just adds a metric ton of tracepoints.
This doesn't fix the current mess, it makes it worse :-(
next prev parent reply other threads:[~2016-09-26 12:27 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-23 16:49 [RFC PATCH v2 0/5] Additional scheduling information in tracepoints Julien Desfossez
2016-09-23 16:49 ` [RFC PATCH v2 1/5] sched: get effective policy and rt_prio Julien Desfossez
2016-09-23 16:49 ` [RFC PATCH v2 2/5] tracing: add TRACE_EVENT_MAP Julien Desfossez
2016-09-23 16:49 ` [RFC PATCH v2 3/5] tracing: extend scheduling tracepoints Julien Desfossez
2016-09-23 16:49 ` [RFC PATCH v2 4/5] tracing: extend sched_pi_setprio Julien Desfossez
2016-09-23 16:49 ` [RFC PATCH v2 5/5] tracing: add sched_update_prio Julien Desfossez
2016-09-24 13:28 ` Mathieu Desnoyers
2016-09-26 12:27 ` Peter Zijlstra [this message]
2016-09-26 19:37 ` [RFC PATCH v2 0/5] Additional scheduling information in tracepoints Mathieu Desnoyers
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