OK, direct the annoying traces to the output folder

Otherwise it was getting messy to distinguish between trace-events
and trace-<pid> in the .gitignore.

Now only the latest trace will be kept, with a fixed name.

.gitignore

@@ -9,7 +9,6 @@ gitignore*
 # Specific files.
 /9p
 /README.html
-/trace-[0-9]*
 
 # GEM5
 /m5out

run

@@ -25,7 +25,8 @@ initramfs=false
 memory=256M
 nographic=true
 root=''
-while getopts a:c:DdE:e:f:G:ghIiKkm:x OPT; do
+trace_enable=''
+while getopts a:c:DdE:e:f:G:ghIiKkm:T:x OPT; do
   case "$OPT" in
     a)
       arch="$OPTARG"
@@ -78,6 +79,9 @@ while getopts a:c:DdE:e:f:G:ghIiKkm:x OPT; do
     m)
       memory="$OPTARG"
       ;;
+    T)
+      trace_enable="$OPTARG"
+      ;;
     x)
       nographic=false
       ;;
@@ -169,6 +173,7 @@ ${debug_vm} \
 -monitor telnet::45454,server,nowait \
 -netdev user,hostfwd=tcp::45455-:45455,hostfwd=tcp::45456-:22,id=net0 \
 -smp ${cpus} \
+-trace enable=${trace_enable},file='${lkmc_out_dir}/trace.bin' \
 -virtfs local,path=9p,mount_tag=host_scratch,security_model=mapped,id=host_scratch \
 -virtfs local,path=${out_dir}/build,mount_tag=host_out,security_model=mapped,id=host_out \
 "

run-usage.adoc

@@ -35,5 +35,10 @@
 |`-K` |              |Use KVM. Only works if guest arch == host arch.
 |`-k` |              |Enable KGDB.
 |`-m` |              |Set the memory size of the guest. E.g.: `-m 512M`. Default: `256M`.
+|`-T` |              |Enable extra QEMU trace events.
+                      `./configure --enable-trace-backends=simple` seems to enable
+                      some by default, e.g. `pr_manager_run`, and I don't know how to
+                      get rid of them. But those events are rare and should not impact
+                      performance, so we just ignore them for now.
 |`-x` |              |Run in graphic mode. Mnemonic: X11.
 |===

trace-boot

@@ -10,7 +10,7 @@ while getopts a: OPT; do
   esac
 done
 set_common_vars "$arch" false
-time ./run -a "$arch" -e 'init=/poweroff.out' -- -trace exec_tb,file="${lkmc_out_dir}/trace.bin"
+time ./run -a "$arch" -e 'init=/poweroff.out' -T exec_tb
 time ./qemu/scripts/simpletrace.py "${out_dir}/build/host-qemu-custom/trace-events-all" "${lkmc_out_dir}/trace.bin" >"${lkmc_out_dir}/trace.txt"
 
 # Instruction count.