| Message ID | 147041637432.2523.7105228834091669652.stgit@fimbulvetr.bsc.es |
|---|---|
| State | New |
| Headers | show |
On Fri, Aug 05, 2016 at 06:59:34PM +0200, Lluís Vilanova wrote: > +# hypertrace > +hyperargs=$hypertrace > +if test $hypertrace = "disabled"; then > + hyperargs=0 > +fi > +echo "CONFIG_HYPERTRACE_ARGS=$hyperargs" >> $config_host_mak > +hypertrace_events=hypertrace/trace-events > +mkdir -p $(dirname $hypertrace_events) > +echo "# See docs/trace-events.txt for syntax documentation." >$hypertrace_events > +echo -n 'vcpu guest_hypertrace(' >>$hypertrace_events > +for i in `seq $hypertrace`; do > + if test $i != 1; then > + echo -n ", " >>$hypertrace_events > + fi > + echo -n "uint64_t arg$i" >>$hypertrace_events > +done > +echo -n ') ' >>$hypertrace_events > +for i in `seq $hypertrace`; do > + echo -n "\" arg$i=0x%016\"PRIx64" >>$hypertrace_events > +done > +echo >>$hypertrace_events This reminds me of the first versions of "simpletrace" where the number of arguments was fixed and argument size was fixed. This meant strings cannot be traced, number of arguments is limited, and you pay an space overhead for unused arguments. Later on the format was changed to header (including .length field) and binary data payload. This reduced the space overhead, elminated the argument count limit, and allowed strings to be traced. I think these are desirable qualities for any tracing mechanism and would reconsider a fixed number of uint64_t arguments. Stefan
Stefan Hajnoczi writes: > On Fri, Aug 05, 2016 at 06:59:34PM +0200, Lluís Vilanova wrote: >> +# hypertrace >> +hyperargs=$hypertrace >> +if test $hypertrace = "disabled"; then >> + hyperargs=0 >> +fi >> +echo "CONFIG_HYPERTRACE_ARGS=$hyperargs" >> $config_host_mak >> +hypertrace_events=hypertrace/trace-events >> +mkdir -p $(dirname $hypertrace_events) >> +echo "# See docs/trace-events.txt for syntax documentation." >$hypertrace_events >> +echo -n 'vcpu guest_hypertrace(' >>$hypertrace_events >> +for i in `seq $hypertrace`; do >> + if test $i != 1; then >> + echo -n ", " >>$hypertrace_events >> + fi >> + echo -n "uint64_t arg$i" >>$hypertrace_events >> +done >> +echo -n ') ' >>$hypertrace_events >> +for i in `seq $hypertrace`; do >> + echo -n "\" arg$i=0x%016\"PRIx64" >>$hypertrace_events >> +done >> +echo >>$hypertrace_events > This reminds me of the first versions of "simpletrace" where the number > of arguments was fixed and argument size was fixed. > This meant strings cannot be traced, number of arguments is limited, and > you pay an space overhead for unused arguments. > Later on the format was changed to header (including .length field) and > binary data payload. This reduced the space overhead, elminated the > argument count limit, and allowed strings to be traced. > I think these are desirable qualities for any tracing mechanism and > would reconsider a fixed number of uint64_t arguments. The number of arguments is fixed at *compilation time*. What is not supported out of the box is multiplexing multiple guest events over the hypertrace event. That is, you need to do it yourself when post-processing the traces, but I don't think that's too bad. Cheers, Lluis
diff --git a/Makefile.objs b/Makefile.objs index 7f1f0a3..1c1b03c 100644 --- a/Makefile.objs +++ b/Makefile.objs @@ -158,3 +158,5 @@ trace-events-y += target-s390x/trace-events trace-events-y += target-ppc/trace-events trace-events-y += qom/trace-events trace-events-y += linux-user/trace-events + +trace-events-gen-y = hypertrace/trace-events diff --git a/configure b/configure index 5ada56d..e80fde4 100755 --- a/configure +++ b/configure @@ -273,6 +273,7 @@ pie="" qom_cast_debug="yes" trace_backends="log" trace_file="trace" +hypertrace="disabled" spice="" rbd="" smartcard="" @@ -782,6 +783,8 @@ for opt do ;; --with-trace-file=*) trace_file="$optarg" ;; + --with-hypertrace-args=*) hypertrace="$optarg" + ;; --enable-gprof) gprof="yes" ;; --enable-gcov) gcov="yes" @@ -1300,6 +1303,8 @@ Advanced options (experts only): Available backends: $($python $source_path/scripts/tracetool.py --list-backends) --with-trace-file=NAME Full PATH,NAME of file to store traces Default:trace-<pid> + --with-hypertrace-args=NUMBER + number of hypertrace arguments (default: disabled) --disable-slirp disable SLIRP userspace network connectivity --enable-tcg-interpreter enable TCG with bytecode interpreter (TCI) --oss-lib path to OSS library @@ -4197,6 +4202,14 @@ if test "$?" -ne 0 ; then fi ########################################## +# check hypertrace arguments +case "$hypertrace" in + disabled) ;; + ''|*[!0-9]*) error_exit "invalid number of hypertrace arguments" ;; + *) ;; +esac + +########################################## # For 'ust' backend, test if ust headers are present if have_backend "ust"; then cat > $TMPC << EOF @@ -4862,6 +4875,7 @@ echo "Trace backends $trace_backends" if have_backend "simple"; then echo "Trace output file $trace_file-<pid>" fi +echo "Hypertrace arguments $hypertrace" echo "spice support $spice $(echo_version $spice $spice_protocol_version/$spice_server_version)" echo "rbd support $rbd" echo "xfsctl support $xfs" @@ -5490,6 +5504,28 @@ else fi QEMU_INCLUDES="-I\$(SRC_PATH)/tcg $QEMU_INCLUDES" +# hypertrace +hyperargs=$hypertrace +if test $hypertrace = "disabled"; then + hyperargs=0 +fi +echo "CONFIG_HYPERTRACE_ARGS=$hyperargs" >> $config_host_mak +hypertrace_events=hypertrace/trace-events +mkdir -p $(dirname $hypertrace_events) +echo "# See docs/trace-events.txt for syntax documentation." >$hypertrace_events +echo -n 'vcpu guest_hypertrace(' >>$hypertrace_events +for i in `seq $hypertrace`; do + if test $i != 1; then + echo -n ", " >>$hypertrace_events + fi + echo -n "uint64_t arg$i" >>$hypertrace_events +done +echo -n ') ' >>$hypertrace_events +for i in `seq $hypertrace`; do + echo -n "\" arg$i=0x%016\"PRIx64" >>$hypertrace_events +done +echo >>$hypertrace_events + echo "TOOLS=$tools" >> $config_host_mak echo "ROMS=$roms" >> $config_host_mak echo "MAKE=$make" >> $config_host_mak diff --git a/trace/Makefile.objs b/trace/Makefile.objs index 4d91b3b..b71ec54 100644 --- a/trace/Makefile.objs +++ b/trace/Makefile.objs @@ -8,7 +8,7 @@ tracetool-y = $(SRC_PATH)/scripts/tracetool.py tracetool-y += $(shell find $(SRC_PATH)/scripts/tracetool -name "*.py") -$(BUILD_DIR)/trace-events-all: $(trace-events-y:%=$(SRC_PATH)/%) +$(BUILD_DIR)/trace-events-all: $(trace-events-y:%=$(SRC_PATH)/%) $(trace-events-gen-y:%=$(BUILD_DIR)/%) $(call quiet-command,cat $^ > $@) ######################################################################
Generates the "guest_hypertrace" event with a user-configurable number of arguments. Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu> --- Makefile.objs | 2 ++ configure | 36 ++++++++++++++++++++++++++++++++++++ trace/Makefile.objs | 2 +- 3 files changed, 39 insertions(+), 1 deletion(-)