Re: [Qemu-devel] [PATCH v3 00/11] simplify usage of tracepoints, and connect them to logging

["Denis V. Lunev" <den@openvz.org>]

On 01/07/2016 12:58 PM, Stefan Hajnoczi wrote:
> On Thu, Oct 29, 2015 at 11:44:06PM +0300, Denis V. Lunev wrote:
>> This series does three things:
>>
>> 1) add a "-trace [enable=]foo" option to enable one or more trace
>> events, and a "-trace help" option to show the list of tracepoints
>> (patches 4-5)
>>
>> 2) change the stderr tracing backend so that it prints to the
>> -D log file, and enable it by default.  "-trace file=..." is
>> now a synonym of -D if the log backend is enabled (patches 7-8)
>>
>> 3) add a "-d trace:foo" option that is a synonym for "-trace foo";
>> this makes the new functionality more discoverable to people used
>> to "-d", makes it available for user-mode emulation (which does
>> not have -trace), and is somewhat nice if you want to enable both
>> tracepoints and some other "-d" flag (patch 9).  When globbing
>> it is also less susceptible to unwanted shell expansion.
>>
>> For example, you can trace block device I/O and save the result
>> to a file just by adding "-trace bdrv_aio_*,file=trace.txt", or
>> correlate it to guest PCs with "-d exec,nochain,trace:bdrv_aio_*".
>>
>> Opinions?  I would like to have this in 2.5 if there is agreement.
>>
>> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
>> Signed-off-by: Denis V. Lunev <den@openvz.org>
>>
>> Changes from v2:
>> - compilation fix was extended to patch 2 and 3
>> - replaced Reviewed-by with Acked-by by request from Christian
>>
>> Changes from v1:
>> - small cleanup to vl.c is added as patch (4)
>> - compilation is fixed in patch (2)
>> - moved qemu-log.c to util/log.c to fix linking of qemu-io/qemu-nbd
>>
>> Denis V. Lunev (2):
>>    trace: no need to call trace_backend_init in different branches now
>>    log: move qemu-log.c into util/ directory
>>
>> Paolo Bonzini (9):
>>    trace: fix documentation
>>    trace: split trace_init_events out of trace_init_backends
>>    trace: split trace_init_file out of trace_init_backends
>>    trace: add "-trace enable=..."
>>    trace: add "-trace help"
>>    log: do not unnecessarily include qom/cpu.h
>>    trace: convert stderr backend to log
>>    trace: switch default backend to "log"
>>    log: add "-d trace:PATTERN"
>>
>>   Makefile.objs                                   |  1 -
>>   bsd-user/main.c                                 |  1 +
>>   configure                                       |  6 +-
>>   cpu-exec.c                                      |  1 +
>>   exec.c                                          |  1 +
>>   hw/acpi/cpu_hotplug.c                           |  1 +
>>   hw/timer/a9gtimer.c                             |  1 +
>>   include/exec/log.h                              | 60 ++++++++++++++++
>>   include/qemu/log.h                              | 60 +---------------
>>   linux-user/main.c                               |  1 +
>>   qemu-io.c                                       |  2 +-
>>   qemu-options.hx                                 | 22 ++++--
>>   qom/cpu.c                                       |  1 +
>>   scripts/tracetool/backend/{stderr.py => log.py} |  9 +--
>>   target-alpha/translate.c                        |  1 +
>>   target-arm/translate.c                          |  1 +
>>   target-cris/translate.c                         |  1 +
>>   target-i386/seg_helper.c                        |  1 +
>>   target-i386/smm_helper.c                        |  1 +
>>   target-i386/translate.c                         |  1 +
>>   target-lm32/helper.c                            |  1 +
>>   target-lm32/translate.c                         |  1 +
>>   target-m68k/translate.c                         |  1 +
>>   target-microblaze/helper.c                      |  1 +
>>   target-microblaze/translate.c                   |  1 +
>>   target-mips/helper.c                            |  1 +
>>   target-mips/translate.c                         |  1 +
>>   target-moxie/translate.c                        |  1 +
>>   target-openrisc/translate.c                     |  1 +
>>   target-ppc/mmu-hash32.c                         |  1 +
>>   target-ppc/mmu-hash64.c                         |  1 +
>>   target-ppc/mmu_helper.c                         |  1 +
>>   target-ppc/translate.c                          |  1 +
>>   target-s390x/translate.c                        |  1 +
>>   target-sh4/helper.c                             |  1 +
>>   target-sh4/translate.c                          |  1 +
>>   target-sparc/int32_helper.c                     |  1 +
>>   target-sparc/int64_helper.c                     |  1 +
>>   target-sparc/translate.c                        |  1 +
>>   target-tilegx/translate.c                       |  1 +
>>   target-tricore/translate.c                      |  1 +
>>   target-unicore32/translate.c                    |  1 +
>>   target-xtensa/translate.c                       |  1 +
>>   tcg/tcg.c                                       |  1 +
>>   trace/control.c                                 | 95 ++++++++++++++++++-------
>>   trace/control.h                                 | 42 ++++++++++-
>>   trace/simple.c                                  |  6 +-
>>   trace/simple.h                                  |  4 +-
>>   translate-all.c                                 |  1 +
>>   util/Makefile.objs                              |  1 +
>>   qemu-log.c => util/log.c                        | 19 ++++-
>>   vl.c                                            | 38 +++++-----
>>   52 files changed, 274 insertions(+), 129 deletions(-)
>>   create mode 100644 include/exec/log.h
>>   rename scripts/tracetool/backend/{stderr.py => log.py} (78%)
>>   rename qemu-log.c => util/log.c (90%)
> Hi Denis,
> I have pasted the issues that Peter Maydell hit during QEMU 2.5 below.
> Please rebase this series onto
> https://github.com/stefanha/qemu/commits/tracing-pull-request
> (cef517ca4bf890ef5405aac1b95f75dcda043d6a)
>
> I'll rerun the Windows build on the next revision to make sure the
> warnings have been fixed.
>
> Thanks,
> Stefan
> ---
>
> 1.
> Fails to build on all platforms :-(
>
> /home/petmay01/linaro/qemu-for-merges/target-arm/translate-a64.c: In
> function ‘gen_intermediate_code_a64’:
> /home/petmay01/linaro/qemu-for-merges/target-arm/translate-a64.c:11229:9:
> error: implicit declaration of function ‘lookup_symbol’
> [-Werror=implicit-function-declaration]
>           qemu_log("IN: %s\n", lookup_symbol(pc_start));
>           ^
> /home/petmay01/linaro/qemu-for-merges/target-arm/translate-a64.c:11229:9:
> error: nested extern declaration of ‘lookup_symbol’
> [-Werror=nested-externs]
> /home/petmay01/linaro/qemu-for-merges/target-arm/translate-a64.c:11229:9:
> error: format ‘%s’ expects argument of type ‘char *’, but argument 2
> has type ‘int’ [-Werror=format=]
> /home/petmay01/linaro/qemu-for-merges/target-arm/translate-a64.c:11230:9:
> error: implicit declaration of function ‘log_target_disas’
> [-Werror=implicit-function-declaration]
>           log_target_disas(cs, pc_start, dc->pc - pc_start,
>           ^
> /home/petmay01/linaro/qemu-for-merges/target-arm/translate-a64.c:11230:9:
> error: nested extern declaration of ‘log_target_disas’
> [-Werror=nested-externs]
> cc1: all warnings being treated as errors
>
> 2.
> w32 fails to build with the same 'ssize_t vs signed size_t for %zd'
> thing that hit somebody else's changes earlier this week:
>
> In file included from /home/petmay01/linaro/qemu-for-merges/include/trace.h:4,
>                   from
> /home/petmay01/linaro/qemu-for-merges/util/oslib-win32.c:38:
> ./trace/generated-tracers.h: In function ‘trace_virtio_console_flush_buf’:
> ./trace/generated-tracers.h:240: warning: format ‘%zd’ expects type
> ‘signed size_t’, but argument 8 has type ‘ssize_t’
>    CC    util/bitops.o
> ./trace/generated-tracers.h: In function ‘trace_usb_ohci_iso_td_so’:
> ./trace/generated-tracers.h:2784: warning: format ‘%zu’ expects type
> ‘size_t’, but argument 11 has type ‘ssize_t’
> ./trace/generated-tracers.h: In function ‘trace_usb_ohci_iso_td_data_overrun’:
> ./trace/generated-tracers.h:2796: warning: format ‘%zu’ expects type
> ‘size_t’, but argument 7 has type ‘ssize_t’
>    CC    util/hbitmap.o
>    CC    util/fifo8.o
> ./trace/generated-tracers.h: In function ‘trace_spice_vmc_write’:
> ./trace/generated-tracers.h:6492: warning: format ‘%zd’ expects type
> ‘signed size_t’, but argument 6 has type ‘ssize_t’
>    CC    util/acl.o
>    CC    util/error.o
> ./trace/generated-tracers.h: In function ‘trace_v9fs_read_return’:
> ./trace/generated-tracers.h:10344: warning: format ‘%zd’ expects type
> ‘signed size_t’, but argument 9 has type ‘ssize_t’
> ./trace/generated-tracers.h: In function ‘trace_v9fs_readdir_return’:
> ./trace/generated-tracers.h:10368: warning: format ‘%zd’ expects type
> ‘signed size_t’, but argument 9 has type ‘ssize_t’
> ./trace/generated-tracers.h: In function ‘trace_v9fs_write_return’:
> ./trace/generated-tracers.h:10392: warning: format ‘%zd’ expects type
> ‘signed size_t’, but argument 9 has type ‘ssize_t’
>    CC    util/qemu-error.o
>    CC    util/id.o
>    CC    util/iov.o
> cc1: warnings being treated as errors
> In file included from /home/petmay01/linaro/qemu-for-merges/include/trace.h:4,
>                   from /home/petmay01/linaro/qemu-for-merges/util/hbitmap.c:18:
> ./trace/generated-tracers.h: In function ‘trace_virtio_console_flush_buf’:
> ./trace/generated-tracers.h:240: warning: format ‘%zd’ expects type
> ‘signed size_t’, but argument 8 has type ‘ssize_t’
>    CC    util/qemu-config.o
> ./trace/generated-tracers.h: In function ‘trace_usb_ohci_iso_td_so’:
> ./trace/generated-tracers.h:2784: warning: format ‘%zu’ expects type
> ‘size_t’, but argument 11 has type ‘ssize_t’
> ./trace/generated-tracers.h: In function ‘trace_usb_ohci_iso_td_data_overrun’:
> ./trace/generated-tracers.h:2796: warning: format ‘%zu’ expects type
> ‘size_t’, but argument 7 has type ‘ssize_t’
> make: *** [util/oslib-win32.o] Error 1
> make: *** Waiting for unfinished jobs....
> ./trace/generated-tracers.h: In function ‘trace_spice_vmc_write’:
> ./trace/generated-tracers.h:6492: warning: format ‘%zd’ expects type
> ‘signed size_t’, but argument 6 has type ‘ssize_t’
> ./trace/generated-tracers.h: In function ‘trace_v9fs_read_return’:
> ./trace/generated-tracers.h:10344: warning: format ‘%zd’ expects type
> ‘signed size_t’, but argument 9 has type ‘ssize_t’
> ./trace/generated-tracers.h: In function ‘trace_v9fs_readdir_return’:
> ./trace/generated-tracers.h:10368: warning: format ‘%zd’ expects type
> ‘signed size_t’, but argument 9 has type ‘ssize_t’
> ./trace/generated-tracers.h: In function ‘trace_v9fs_write_return’:
> ./trace/generated-tracers.h:10392: warning: format ‘%zd’ expects type
> ‘signed size_t’, but argument 9 has type ‘ssize_t’
> make: *** [util/hbitmap.o] Error 1
> make: Leaving directory `/home/petmay01/linaro/qemu-for-merges/build/w32'
>
> 3.
> I also now get a handful of extra warnings in the 'make check' output:
>
>    /aarch64/qom/xilinx-zynq-a9:                                         OK
>    /aarch64/qom/xlnx-ep108:
> WARNING: RAM size 8000000 is small for EP108OK
>    /aarch64/qom/vexpress-a9:                                            OK
>
> (note the missing newline...)
>
> TEST: tests/qom-test... (pid=19738)
>    /microblaze/qom/none:                                                OK
>    /microblaze/qom/petalogix-s3adsp1800:
> Invalid MicroBlaze version number: (null)
> OK
>    /microblaze/qom/petalogix-ml605:
> Invalid MicroBlaze version number: (null)
> OK
got this