From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 77936C433FE for ; Thu, 2 Dec 2021 12:33:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230360AbhLBMg1 (ORCPT ); Thu, 2 Dec 2021 07:36:27 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38434 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346987AbhLBMg1 (ORCPT ); Thu, 2 Dec 2021 07:36:27 -0500 Received: from mail-ed1-x529.google.com (mail-ed1-x529.google.com [IPv6:2a00:1450:4864:20::529]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AD0AFC06174A for ; Thu, 2 Dec 2021 04:33:04 -0800 (PST) Received: by mail-ed1-x529.google.com with SMTP id x15so115231133edv.1 for ; Thu, 02 Dec 2021 04:33:04 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=+cwRbIwuoZEoyKcE+k5ZGc5ve+d995rwGCr1GRVh+ks=; b=kiux8cwautBiXBC4jf1wKXSSKN0JUTcnnAPGmI6i/MoQH4W/C5iuu8ZqUifMoXhE45 BpSyhYdIR+RvtokSepIAIY0hvNEAL+rw5XjQnMoN9LsYRSMb8ZFG8LqO3tmEh7PpW2AN t6jiCSOGwDAwK1xdNlG+NXWYSmF+JT+xXF1DLqxffvnovaPDSZ/3XHpK7MM+SS6rq2cm Uo12bgPjRc/ZngeaVjxa26LoPctZsptSzFzfzYqUlLJHiUpWY0nNhM82WYOJPRKP6KUj Qs//SeBEnZWqXP2ekFyV9VjwOAdtG5XuF/NDRR9AWAjDRgLPdePq14geZBlL/xDZmXiY XkEw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=+cwRbIwuoZEoyKcE+k5ZGc5ve+d995rwGCr1GRVh+ks=; b=kauZaeQx0oOmmdC2ngb27QvhVL4rT52akHxJuhQmWVJ1FxvpQK2/BqXAc3uuSNVSgf hRlQoQidLy0pNGKrRMS6+PzHzQgbgOntpB5olUaSaqEY+6FqV/578eMi3haS4ujRVFzf HfMNNXKCnXa43UUAVaQ/5YO0wj2Y7qxeopD9rOJexapPhk4sXMPOeqZDt5Zac0J9RJ3a DL9PT0dJ7+9ycsEqbstm/PugA6qulhNUBrPIcqML6BNrqZ0+flvU8t50K0UV76Di4yNX T9efRymPpNxAw5X2ejPm2ebqGzzSUpsOhrxp793OPkytxEKzEZf1wVU2ziipdwE0/EJy o2rQ== X-Gm-Message-State: AOAM530jKZ9X1LxHA7g7hNWvDbC19sIz9M1EAx8bvXfJstDOzfw3oxT5 UbfYNdNXwraV8szmd8X5kL80H5tkU38H+Q== X-Google-Smtp-Source: ABdhPJzmnPY2CyFqhF4qsny/q2WQlTxS45pPAJn9jvQiHZcpvP2NMa9N5VrDpMyxtM6w7/b58WThUQ== X-Received: by 2002:a17:907:7664:: with SMTP id kk4mr14592578ejc.319.1638448383203; Thu, 02 Dec 2021 04:33:03 -0800 (PST) Received: from oberon.zico.biz.zico.biz ([83.222.187.186]) by smtp.gmail.com with ESMTPSA id g9sm2188420edb.52.2021.12.02.04.33.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 02 Dec 2021 04:33:02 -0800 (PST) From: "Tzvetomir Stoyanov (VMware)" To: rostedt@goodmis.org Cc: linux-trace-devel@vger.kernel.org Subject: [PATCH v3 1/2] trace-cmd library: Use the real trace buffer page size Date: Thu, 2 Dec 2021 14:32:59 +0200 Message-Id: <20211202123300.44401-2-tz.stoyanov@gmail.com> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20211202123300.44401-1-tz.stoyanov@gmail.com> References: <20211202123300.44401-1-tz.stoyanov@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@vger.kernel.org When new output handler is created, it assumes that the trace buffer page size is equal to the system memory page size. This assumption is valid for the current ftrace implementation, but it may change in the future. The newly introduced traceevent library API should be used to get the real trace buffer page size, bases on the information from the "events/header_page" ftrace file. This commit depends on: [PATCH] libtraceevent: A new API for trace page size https://lore.kernel.org/linux-trace-devel/20211001062338.2389024-1-tz.stoyanov@gmail.com/ Signed-off-by: Tzvetomir Stoyanov (VMware) --- lib/trace-cmd/trace-output.c | 37 +++++++++++++++++++++++++++++++++++- 1 file changed, 36 insertions(+), 1 deletion(-) diff --git a/lib/trace-cmd/trace-output.c b/lib/trace-cmd/trace-output.c index 8751e168..0edd0c52 100644 --- a/lib/trace-cmd/trace-output.c +++ b/lib/trace-cmd/trace-output.c @@ -1195,6 +1195,41 @@ static int write_compression_header(struct tracecmd_output *handle) return 0; } +static int get_trace_page_size(struct tracecmd_output *handle) +{ + struct tracefs_instance *instance; + struct tep_handle *tep = NULL; + int psize, size; + char *buff = NULL; + + /* In case of an error, return user space page size */ + psize = getpagesize(); + + instance = tracefs_instance_alloc(find_tracing_dir(handle), NULL); + if (!instance) + goto out; + + buff = tracefs_instance_file_read(instance, "events/header_page", &size); + if (!buff) + goto out; + + tep = tep_alloc(); + if (!tep) + goto out; + + if (tep_parse_header_page(tep, buff, size, sizeof(long long))) + goto out; + + psize = tep_get_sub_buffer_size(tep); + +out: + tracefs_instance_free(instance); + tep_free(tep); + free(buff); + + return psize; +} + /** * tracecmd_output_create_fd - allocate new output handle to a trace file * @fd: File descriptor for the handle to write to. @@ -1219,7 +1254,7 @@ struct tracecmd_output *tracecmd_output_create_fd(int fd) handle->file_version = FILE_VERSION_DEFAULT; - handle->page_size = getpagesize(); + handle->page_size = get_trace_page_size(handle); handle->big_endian = tracecmd_host_bigendian(); list_head_init(&handle->options); -- 2.33.1