From patchwork Thu Nov 29 12:23:42 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tzvetomir Stoyanov X-Patchwork-Id: 10760067 Return-Path: Received: from mail-eopbgr800053.outbound.protection.outlook.com ([40.107.80.53]:16334 "EHLO NAM03-DM3-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726683AbeK2X25 (ORCPT ); Thu, 29 Nov 2018 18:28:57 -0500 From: Tzvetomir Stoyanov To: "rostedt@goodmis.org" CC: "linux-trace-devel@vger.kernel.org" Subject: [POC][PATCH v4] tools/lib/traceevent: make libtraceevent thread safe Date: Thu, 29 Nov 2018 12:23:42 +0000 Message-ID: <20181129122330.22500-1-tstoyanov@vmware.com> Content-Language: en-US MIME-Version: 1.0 Sender: linux-trace-devel-owner@vger.kernel.org List-ID: Content-Length: 6213 This patch is a PoC about transforming libtraceevent into a thread safe library. It implements per thread local storage and internal APIs to access it. It covers only tep->last_event cache, but easily can be extended with all library's thread sensitive data. Signed-off-by: Tzvetomir Stoyanov --- v2: Added local thread data per tep context v3: Implemented APIs to access specific tread local data, instead of the whole struct tep_thread_data. v4: Simplify the implementation to keep cache only for the last used tep context in current thread, instead to track cache for all tep contexts. Remove "tep_" prefix of functions, as these are internal APIs and are not going to be exposed to the library users. --- tools/lib/traceevent/event-parse-local.h | 16 ++++-- tools/lib/traceevent/event-parse-thread.c | 62 +++++++++++++++++++++++ tools/lib/traceevent/event-parse.c | 21 ++++---- 3 files changed, 87 insertions(+), 12 deletions(-) create mode 100644 tools/lib/traceevent/event-parse-thread.c diff --git a/tools/lib/traceevent/event-parse-local.h b/tools/lib/traceevent/event-parse-local.h index 9a092dd4a86d..bf3f810ce02f 100644 --- a/tools/lib/traceevent/event-parse-local.h +++ b/tools/lib/traceevent/event-parse-local.h @@ -14,6 +14,13 @@ struct func_list; struct event_handler; struct func_resolver; +/* cache */ +struct tep_thread_data { + struct tep_handle *tep; + + struct tep_event *last_event; +}; + struct tep_handle { int ref_count; @@ -83,9 +90,6 @@ struct tep_handle { struct event_handler *handlers; struct tep_function_handler *func_handlers; - /* cache */ - struct tep_event *last_event; - char *trace_clock; }; @@ -96,4 +100,10 @@ unsigned short tep_data2host2(struct tep_handle *pevent, unsigned short data); unsigned int tep_data2host4(struct tep_handle *pevent, unsigned int data); unsigned long long tep_data2host8(struct tep_handle *pevent, unsigned long long data); +/* tep cache per thread */ +struct tep_event *get_thread_local_event_by_id(struct tep_handle *tep, int id); +struct tep_event * +get_thread_local_event_by_name(struct tep_handle *tep, const char *name, const char *sys); +void set_thread_local_event_cache(struct tep_handle *tep, struct tep_event *event); + #endif /* _PARSE_EVENTS_INT_H */ diff --git a/tools/lib/traceevent/event-parse-thread.c b/tools/lib/traceevent/event-parse-thread.c new file mode 100644 index 000000000000..b575f7d8424e --- /dev/null +++ b/tools/lib/traceevent/event-parse-thread.c @@ -0,0 +1,62 @@ +// SPDX-License-Identifier: LGPL-2.1 +/* + * Copyright (C) 2009, 2010 Red Hat Inc, Steven Rostedt + * + */ + +#include "event-parse.h" +#include "event-parse-local.h" +#include "event-utils.h" + +static __thread struct tep_thread_data tep_thread_local; + +/** + * get_thread_local_event_by_id - Find event with given id in the cache + * @tep: a handle to the tep context + * @id: event's id + * + * Searches in the cache for event with given id + */ +struct tep_event *get_thread_local_event_by_id(struct tep_handle *tep, int id) +{ + + if (tep_thread_local->last_event && tep_thread_local->tep == tep && + tep_thread_local->last_event->id == id) + return tep_thread_local->last_event; + + return NULL; +} + +/** + * get_thread_local_event_by_name - Find event with given name and sys in the cache + * @tep: a handle to the tep context + * @name: event's name + * @sys: event's system + * + * Searches in the cache for event with given name and system + */ +struct tep_event * +get_thread_local_event_by_name(struct tep_handle *tep, const char *name, const char *sys) +{ + if (tep_thread_local->last_event && + tep_thread_local->tep == tep && + strcmp(tep_thread_local->last_event->name, name) == 0 && + (!sys || strcmp(tep_thread_local->last_event->system, sys) == 0)) + return tep_thread_local->last_event; + + return NULL; +} + +/** + * set_thread_local_event_cache - set last used event in the cache + * @tep: a handle to the tep context + * @event: pointer to the last used event + * + * Sets last used event in the cache, to speed up the next searches + */ +void set_thread_local_event_cache(struct tep_handle *tep, struct tep_event *event) +{ + tep_thread_local->last_event = event; +} + + diff --git a/tools/lib/traceevent/event-parse.c b/tools/lib/traceevent/event-parse.c index a5048c1b9bec..ea6292c61ad4 100644 --- a/tools/lib/traceevent/event-parse.c +++ b/tools/lib/traceevent/event-parse.c @@ -3485,10 +3485,11 @@ struct tep_event *tep_find_event(struct tep_handle *pevent, int id) struct tep_event **eventptr; struct tep_event key; struct tep_event *pkey = &key; + struct tep_event *event_cache = get_thread_local_event_by_id(pevent, id); /* Check cache first */ - if (pevent->last_event && pevent->last_event->id == id) - return pevent->last_event; + if (event_cache) + return event_cache; key.id = id; @@ -3496,7 +3497,7 @@ struct tep_event *tep_find_event(struct tep_handle *pevent, int id) sizeof(*pevent->events), events_id_cmp); if (eventptr) { - pevent->last_event = *eventptr; + set_thread_local_event_cache(pevent, *eventptr); return *eventptr; } @@ -3516,13 +3517,13 @@ struct tep_event * tep_find_event_by_name(struct tep_handle *pevent, const char *sys, const char *name) { - struct tep_event *event = NULL; int i; + struct tep_event *event = NULL; + struct tep_event *event_cache = get_thread_local_event_by_name(pevent, name, sys); - if (pevent->last_event && - strcmp(pevent->last_event->name, name) == 0 && - (!sys || strcmp(pevent->last_event->system, sys) == 0)) - return pevent->last_event; + /* Check cache first */ + if (event_cache) + return event_cache; for (i = 0; i < pevent->nr_events; i++) { event = pevent->events[i]; @@ -3533,10 +3534,12 @@ tep_find_event_by_name(struct tep_handle *pevent, break; } } + if (i == pevent->nr_events) event = NULL; + if (event) + set_thread_local_event_cache(pevent, event); - pevent->last_event = event; return event; }