Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752899AbbDGApI (ORCPT ); Mon, 6 Apr 2015 20:45:08 -0400 Received: from mail7.hitachi.co.jp ([133.145.228.42]:38396 "EHLO mail7.hitachi.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752753AbbDGApF (ORCPT ); Mon, 6 Apr 2015 20:45:05 -0400 Message-ID: <5523288A.4030505@hitachi.com> Date: Tue, 07 Apr 2015 09:44:58 +0900 From: Masami Hiramatsu Organization: Hitachi, Ltd., Japan User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:13.0) Gecko/20120614 Thunderbird/13.0.1 MIME-Version: 1.0 To: Steven Rostedt CC: linux-kernel@vger.kernel.org, Ingo Molnar , Andrew Morton , Namhyung Kim , Mathieu Desnoyers Subject: Re: [RFC][PATCH 00/17 v2] tracing: Use TRACE_DEFINE_ENUM() to show enum values References: <20150402015648.249824760@goodmis.org> In-Reply-To: <20150402015648.249824760@goodmis.org> Content-Type: text/plain; charset=ISO-2022-JP Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5042 Lines: 119 (2015/04/02 10:56), Steven Rostedt wrote: > As there are many tracepoints that use __print_symbolic() to translate > numbers into ASCII strings, and several of these translate enums as > well, it causes a problem for user space tools that read the tracepoint > format files and have to translate the binary data to their associated > strings. > > For example, with the tlb_flush tracepoint, we have this in the format > file: > > print fmt: "pages:%ld reason:%s (%d)", REC->pages, > __print_symbolic(REC->reason, > { TLB_FLUSH_ON_TASK_SWITCH, "flush on task switch" }, > { TLB_REMOTE_SHOOTDOWN, "remote shootdown" }, > { TLB_LOCAL_SHOOTDOWN, "local shootdown" }, > { TLB_LOCAL_MM_SHOOTDOWN, "local mm shootdown" }), REC->reason > > Now, userspace does not know what the value of TLB_REMOTE_SHOOTDOWN is. > To solve this, a new macro is created as a helper to allow tracepoints > to export enums they use to userspace. This macro is called, > TRACE_DEFINE_ENUM(), such that > > TRACE_DEFINE_ENUM(TLB_REMOTE_SHOOTDOWN); > > will convert the "print fmt"s in the format files to its actual value > and no longer display the enum name. > > On boot up (or module load), the enums saved via TRACE_DEFINE_ENUM() > will be searched for in the TP_printk()s of the tracepoints. Logic > knows enough to ignore quoted text. > > For debugging, a new file is still added in the tracing directory > to show what enums were added, their values and the TRACE_SYSTEM that > added them: > > # cat /sys/kernel/debug/tracing/enum_map > TLB_LOCAL_MM_SHOOTDOWN 3 (tlb) > TLB_LOCAL_SHOOTDOWN 2 (tlb) > TLB_REMOTE_SHOOTDOWN 1 (tlb) > TLB_FLUSH_ON_TASK_SWITCH 0 (tlb) > > And the output of the tlb_flush format is now: > > print fmt: "pages:%ld reason:%s (%d)", REC->pages, > __print_symbolic(REC->reason, > { 0, "flush on task switch" }, > { 1, "remote shootdown" }, > { 2, "local shootdown" }, > { 3, "local mm shootdown" }), REC->reason > > And userspace tools can easily parse that without special handling. Great! :) Thank you for updating the series :D Now I'm OK for this series. > > Local SHA1: a6862181206543b6493c73690f322868c86de0ea > > > Steven Rostedt (Red Hat) (17): > tracing: Add TRACE_SYSTEM_VAR to intel-sst > tracing: Add TRACE_SYSTEM_VAR to kvm-s390 > tracing: Add TRACE_SYSTEM_VAR to xhci-hcd > tracing: Give system name a pointer > tracing: Update trace-event-sample with TRACE_SYSTEM_VAR documentation > tracing: Add TRACE_DEFINE_ENUM() macro to map enums to their values > tracing: Allow for modules to export their trace enums as well > tracing/samples: Update the trace-event-sample.h with TRACE_DEFINE_ENUM() > tracing: Show the mapped enums in enum_map file > x86/tlb/trace: Export enums in used by tlb_flush tracepoint > net/9p/tracing: Export enums in tracepoints to userspace > f2fs: Export the enums in the tracepoints to userspace > irq/tracing: Export enums in tracepoints to user space > mm: tracing: Export enums in tracepoints to user space > SUNRPC: Export enums in tracepoints to user space > v4l: Export enums used by tracepoints to user space > writeback: Export enums used by tracepoint to user space > > ---- > arch/s390/kvm/trace-s390.h | 7 + > drivers/usb/host/xhci-trace.h | 7 + > include/asm-generic/vmlinux.lds.h | 5 +- > include/linux/ftrace_event.h | 4 +- > include/linux/module.h | 2 + > include/linux/tracepoint.h | 8 + > include/trace/events/9p.h | 157 ++++++++-------- > include/trace/events/f2fs.h | 30 ++++ > include/trace/events/intel-sst.h | 7 + > include/trace/events/irq.h | 39 ++-- > include/trace/events/migrate.h | 42 +++-- > include/trace/events/sunrpc.h | 62 +++++-- > include/trace/events/tlb.h | 30 +++- > include/trace/events/v4l2.h | 75 +++++--- > include/trace/events/writeback.h | 33 +++- > include/trace/ftrace.h | 41 ++++- > kernel/module.c | 3 + > kernel/trace/trace.c | 276 ++++++++++++++++++++++++++++- > kernel/trace/trace.h | 2 + > kernel/trace/trace_events.c | 98 +++++++++- > samples/trace_events/trace-events-sample.h | 84 ++++++++- > 21 files changed, 853 insertions(+), 159 deletions(-) > > -- Masami HIRAMATSU Linux Technology Research Center, System Productivity Research Dept. Center for Technology Innovation - Systems Engineering Hitachi, Ltd., Research & Development Group E-mail: masami.hiramatsu.pt@hitachi.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/