From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:37875) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RkVbZ-0000dh-0S for qemu-devel@nongnu.org; Tue, 10 Jan 2012 01:54:46 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RkVbW-00051e-Sf for qemu-devel@nongnu.org; Tue, 10 Jan 2012 01:54:44 -0500 Received: from e23smtp07.au.ibm.com ([202.81.31.140]:56668) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RkVbW-00050x-2B for qemu-devel@nongnu.org; Tue, 10 Jan 2012 01:54:42 -0500 Received: from /spool/local by e23smtp07.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 10 Jan 2012 06:50:48 +1000 Received: from d23av01.au.ibm.com (d23av01.au.ibm.com [9.190.234.96]) by d23relay04.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id q0A6nuWa3567664 for ; Tue, 10 Jan 2012 17:49:56 +1100 Received: from d23av01.au.ibm.com (loopback [127.0.0.1]) by d23av01.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id q0A6sG2s001789 for ; Tue, 10 Jan 2012 17:54:17 +1100 Message-ID: <4F0BE091.3020704@linux.vnet.ibm.com> Date: Tue, 10 Jan 2012 12:24:09 +0530 From: Harsh Bora MIME-Version: 1.0 References: <1326123980-6038-1-git-send-email-harsh@linux.vnet.ibm.com> <20120109160105.GA2444@Krystal> <4F0B3E0E.3040505@linux.vnet.ibm.com> <20120110001453.GA8203@Krystal> In-Reply-To: <20120110001453.GA8203@Krystal> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] [RFC PATCH v2 0/4] simpletrace : support var num of args and strings. List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Mathieu Desnoyers Cc: aneesh.kumar@linux.vnet.ibm.com, lttng-dev@lists.lttng.org, qemu-devel@nongnu.org, stefanha@linux.vnet.ibm.com, vilanova@ac.upc.edu On 01/10/2012 05:44 AM, Mathieu Desnoyers wrote: > * Harsh Bora (harsh@linux.vnet.ibm.com) wrote: >> On 01/09/2012 09:31 PM, Mathieu Desnoyers wrote: >>> * Harsh Prateek Bora (harsh@linux.vnet.ibm.com) wrote: >>>> Existing simple trace can log upto 6 args per trace event and does not >>>> support strings in trace record format. Introducing new trace format as >>>> discussed earlier on list to support variable number/size of arguments. >>>> (Ref: http://lists.gnu.org/archive/html/qemu-devel/2011-11/msg03426.html) >>>> >>>> Basic testing of this patch is successful. Stress testing not yet done. >>>> >>>> Apply patches, then run: >>>> >>>> make distclean >>>> ./configure with --enable-trace-backend=simple >>>> make >>>> sudo make install >>>> >>>> Sample tracelog showing strings support: >>>> [harsh@harshbora v9fs]$ scripts/simpletrace.py trace-events trace-23261 >>>> v9fs_version 0.000 tag=65535 id=100 msize=8192 version=9P2000.L >>>> v9fs_version_return 17.530 tag=65535 id=100 msize=8192 version=9P2000.L >>>> v9fs_attach 180.121 tag=1 id=104 fid=0 afid=18446744073709551615 >>>> uname=nobody aname= >>>> >>>> >>>> Note: LTTng ust backend is broken in upstream qemu, therefore tracetool.py >>>> doesnt support ust backend as of now. IIUC, ust's trace event APIs are under >>>> development and not yet stable. >>> >>> Hi, >>> >>> FYI, the LTTng-UST TRACEPOINT_EVENT API is very much stable as of now. >>> Even though we are still in LTTng-UST 2.0 prereleases, the fact that we >>> started the round of discussions on this API last summer makes us >>> confident that from this point on we should not have to change it. >>> >>> Moreover, I would like to know if the old UST 0.x (0.16 is the latest) >>> is broken wrt qemu, or if this is just for LTTng-2.0 UST support ? >>> UST 0.x instrumentation is not supposed to have broken wrt qemu. >>> >> >> Hi, >> Thanks for an early response. I had tried building with ust 0.16 and it >> gives compilation errors, specially for trace events with 'void' >> argument: >> >> CC osdep.o >> In file included from osdep.c:49: >> trace.h: In function ‘__trace_ust_slavio_misc_update_irq_raise’: >> trace.h:277: error: ‘void’ must be the only parameter >> trace.h:277: error: expected expression before ‘)’ token >> trace.h:277: error: too many arguments to function ‘(void (*)(void >> *))__tp_it_func’ >> trace.h: At top level: >> trace.h:277: error: ‘void’ must be the only parameter >> trace.h:277: error: ‘void’ must be the only parameter >> In file included from osdep.c:49: >> trace.h: In function ‘__trace_ust_slavio_misc_update_irq_lower’: >> trace.h:280: error: ‘void’ must be the only parameter >> trace.h:280: error: expected expression before ‘)’ token >> trace.h:280: error: too many arguments to function ‘(void (*)(void >> *))__tp_it_func’ >> >> >> I am not sure which interface is supposed to be used for void arguments >> in ust 0.16. > > Looking at scripts/tracetool: > > linetoh_ust() > { > local name args argnames > name=$(get_name "$1") > args=$(get_args "$1") > argnames=$(get_argnames "$1", ",") > > cat< DECLARE_TRACE(ust_$name, TP_PROTO($args), TP_ARGS($argnames)); > #define trace_$name trace_ust_$name > EOF > } > > for those tracepoints with argument "void", DECLARE_TRACE_NOARGS should > be used for UST 0.16. Similar for: > > DEFINE_TRACE(ust_$name); -> DEFINE_TRACE_NOARGS(ust_$name); > I had tried with _NOARGS variants initially by manually changing the auto-generated code like this: In trace.h: DECLARE_TRACE_NOARGS(ust_slavio_misc_update_irq_raise); #define trace_slavio_misc_update_irq_raise trace_ust_slavio_misc_update_irq_raise In trace.c: DEFINE_TRACE_NOARGS(ust_slavio_misc_update_irq_raise); static void ust_slavio_misc_update_irq_raise_probe() { trace_mark(ust, slavio_misc_update_irq_raise); } However, it still gave error like this: [harsh@harshbora v9fs]$ make CC osdep.o cc1: warnings being treated as errors In file included from osdep.c:49: trace.h:277: error: data definition has no type or storage class trace.h:277: error: type defaults to ‘int’ in declaration of ‘DECLARE_TRACE_NOARGS’ trace.h:277: error: parameter names (without types) in function declaration It will be great if you can provide a sample code (to be auto-generated) required for a trace-event with void argument. - Harsh >> Moreover, if ust 2.0 uses different interfaces, we might >> want to use the latest one. > > Note that this kind of special-case won't be needed with LTTng-UST 2.0 > TRACEPOINT_EVENT. In place of DECLARE_TRACE, one would use: > > TRACEPOINT_EVENT(qemu_kvm, $name, > TP_ARGS($args), > TP_FIELDS() > ) > > Note that I notice that some care will need to be taken to generate the > TP_FIELDS() from your existing trace-events file, an example: > > g_realloc(void *ptr, size_t size, void *newptr) > > would have to be translated to: > > TRACE_EVENT(qemu_kvm, g_realloc, > TP_ARGS(void *, ptr, size_t, size, void *, newptr), > TP_FIELDS( > ctf_integer_hex(void *, ptr, ptr) > ctf_integer(size_t, size, size) > ctf_integer_hex(void *, newptr, newptr) > ) > ) > > Note that the bright side is that the tracepoint probe does not need to > be hand-coded anymore, and there is no need to use the markers anymore > neither, which makes the tracer much faster. > > For most of your fields (using %p, %d style format strings), you should > use ctf_integer or ctf_integer_hex (the latter lets the trace viewer > know that the data should be printed as hexadecimal). > You will likely need to detect the %s format strings you have there and > translate them into ctf_string(field, field) too. You can have a look at > lttng-ust tests/hello/*.[ch] for examples. Thanks for the info, I will look into it later. > > The call which would have looked like trace_qemu_kvm_g_realloc() in UST > 0.x should now be done with: > > tracepoint(qemu_kvm, g_realloc, ptr, size, newptr); > > This is needed to (very soon) add support for sdt.h in LTTng-UST 2.0, so > systemtap and gdb can hook into tracepoints declared by lttng-ust 2.0. > > Best regards, > > Mathieu > >> >> regards, >> Harsh >> >>> Best regards, >>> >>> Mathieu >>> >>>> >>>> Version History: >>>> >>>> v2: >>>> - Updated tracetool.py to support nop, stderr, dtrace backend >>>> >>>> v1: >>>> - Working protoype with tracetool.py converted only for simpletrace backend >>>> >>>> Harsh Prateek Bora (4): >>>> Converting tracetool.sh to tracetool.py >>>> Makefile and configure changes for tracetool.py >>>> simpletrace-v2: Handle variable number/size of elements per trace >>>> record. >>>> simpletrace.py: updated log reader script to handle new log format >>>> >>>> Makefile.objs | 6 +- >>>> Makefile.target | 10 +- >>>> configure | 4 +- >>>> monitor.c | 2 +- >>>> scripts/simpletrace.py | 110 ++++++++++- >>>> scripts/tracetool.py | 505 ++++++++++++++++++++++++++++++++++++++++++++++++ >>>> trace/simple.c | 178 ++++++----------- >>>> trace/simple.h | 31 +++- >>>> 8 files changed, 702 insertions(+), 144 deletions(-) >>>> create mode 100755 scripts/tracetool.py >>>> >>> >> >