From patchwork Thu Jul 22 15:58:45 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 59612 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [199.232.76.165]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 51F051007D7 for ; Fri, 23 Jul 2010 02:36:17 +1000 (EST) Received: from localhost ([127.0.0.1]:44998 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Obyko-0007N7-IK for incoming@patchwork.ozlabs.org; Thu, 22 Jul 2010 12:36:14 -0400 Received: from [140.186.70.92] (port=53828 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1ObyAy-0007AS-3C for qemu-devel@nongnu.org; Thu, 22 Jul 2010 11:59:14 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1ObyAv-0002NN-R9 for qemu-devel@nongnu.org; Thu, 22 Jul 2010 11:59:11 -0400 Received: from mtagate2.uk.ibm.com ([194.196.100.162]:58027) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1ObyAv-0002N4-Jt for qemu-devel@nongnu.org; Thu, 22 Jul 2010 11:59:09 -0400 Received: from d06nrmr1407.portsmouth.uk.ibm.com (d06nrmr1407.portsmouth.uk.ibm.com [9.149.38.185]) by mtagate2.uk.ibm.com (8.13.1/8.13.1) with ESMTP id o6MFx8FS004781 for ; Thu, 22 Jul 2010 15:59:08 GMT Received: from d06av01.portsmouth.uk.ibm.com (d06av01.portsmouth.uk.ibm.com [9.149.37.212]) by d06nrmr1407.portsmouth.uk.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id o6MFx2F6921822 for ; Thu, 22 Jul 2010 16:59:08 +0100 Received: from d06av01.portsmouth.uk.ibm.com (loopback [127.0.0.1]) by d06av01.portsmouth.uk.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id o6MFx2Vv005920 for ; Thu, 22 Jul 2010 16:59:02 +0100 Received: from stefan-thinkpad.manchester-maybrook.uk.ibm.com (dyn-9-174-219-33.manchester-maybrook.uk.ibm.com [9.174.219.33]) by d06av01.portsmouth.uk.ibm.com (8.12.11.20060308/8.12.11) with ESMTP id o6MFx1Ns005887; Thu, 22 Jul 2010 16:59:01 +0100 From: Stefan Hajnoczi To: Date: Thu, 22 Jul 2010 16:58:45 +0100 Message-Id: <1279814326-9422-3-git-send-email-stefanha@linux.vnet.ibm.com> X-Mailer: git-send-email 1.7.1 In-Reply-To: <1279814326-9422-1-git-send-email-stefanha@linux.vnet.ibm.com> References: <1279814326-9422-1-git-send-email-stefanha@linux.vnet.ibm.com> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6, seldom 2.4 (older, 4) Cc: Stefan Hajnoczi , Prerna Saxena Subject: [Qemu-devel] [Tracing] [PATCH 3/4] Add a header to the trace file format X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org The trace file format needs a header so that future extension is possible. There is a version number that can be bumped when file format changes are made. There is still the issue of endianness and sizeof(long). This patch does not address those. Signed-off-by: Stefan Hajnoczi --- simpletrace.c | 17 ++++++++++++++++- simpletrace.py | 33 ++++++++++++++++++++++++++------- 2 files changed, 42 insertions(+), 8 deletions(-) diff --git a/simpletrace.c b/simpletrace.c index 71110b3..df21609 100644 --- a/simpletrace.c +++ b/simpletrace.c @@ -28,6 +28,17 @@ void st_print_trace_file_status(FILE *stream, int (*stream_printf)(FILE *stream, getpid(), trace_file_enabled ? "on" : "off"); } +static bool write_header(FILE *fp) +{ + TraceRecord header = { + .event = -1UL, /* max avoids conflicting with TraceEventIDs */ + .timestamp_ns = 0xf2b177cb0aa429b4, /* magic number */ + .x1 = 0, /* bump this version number if file format changes */ + }; + + return fwrite(&header, sizeof header, 1, fp) == 1; +} + static bool open_trace_file(void) { char *filename; @@ -38,7 +49,11 @@ static bool open_trace_file(void) trace_fp = fopen(filename, "w"); free(filename); - return trace_fp != NULL; + if (!trace_fp) { + return false; + } + + return write_header(trace_fp); } static void flush_trace_file(void) diff --git a/simpletrace.py b/simpletrace.py index c951023..16ab2e7 100755 --- a/simpletrace.py +++ b/simpletrace.py @@ -13,10 +13,18 @@ import sys import struct import re +header_event_id = 0xffffffffffffffff +header_magic = 0xf2b177cb0aa429b4 +header_version = 0 + trace_fmt = 'LLLLLLL' trace_len = struct.calcsize(trace_fmt) event_re = re.compile(r'(disable\s+)?([a-zA-Z0-9_]+)\(([^)]*)\)\s+"([^"]*)"') +def err(msg): + sys.stderr.write(msg + '\n') + sys.exit(1) + def parse_events(fobj): """Parse a trace-events file.""" @@ -46,6 +54,22 @@ def read_record(fobj): return None return struct.unpack(trace_fmt, s) +def read_trace_file(fobj): + """Deserialize trace records from a file.""" + header = read_record(fobj) + if header is None or \ + header[0] != header_event_id or \ + header[1] != header_magic or \ + header[2] != header_version: + err('not a trace file or incompatible version') + + while True: + rec = read_record(fobj) + if rec is None: + break + + yield rec + class Formatter(object): """Trace record pretty-printer""" @@ -67,15 +91,10 @@ class Formatter(object): return ' '.join(fields) if len(sys.argv) != 3: - sys.stderr.write('usage: %s \n' % sys.argv[0]) - sys.exit(1) + err('usage: %s ' % sys.argv[0]) events = parse_events(open(sys.argv[1], 'r')) f = open(sys.argv[2], 'rb') formatter = Formatter(events) -while True: - rec = read_record(f) - if rec is None: - break - +for rec in read_trace_file(f): print formatter.format_record(rec)