I've just noticed that Fedora is using pretty old gperftools.
give me some time to try the latest release

well, I tested on 2.15, the same zero size haproxy.prof

This is because profile is dumped on program shutdown. If it dies from signal, there is no profile flushing.

Have your program stop normally, or have it stop normally on signal. Or arrange profiling for specific duration and Stop it yourself.

As somewhat crude (and not 100% reliable) workaround people have contributed CPUPROFILESIGNAL. Which allows you to toggle profiling on/off by sending that signal. Feel free to look it up in the code.

Yes, we could turn our profile dumping design to be continuous (via mmap-ed files) and crash-only. But this is an enhancement.

Let me turn this ticket into such enhancement. If there is anyone willing to volunteer several days of work into this, I am willing to guide such person.

hello, @alk

thank you for you help. I previously tried CPUPROFILESIGNAL, but it also behaves in strange way
as far as I understand, I must send a signal twice: to begin collecting and to end collecting.

git clone https://github.com/haproxy/haproxy
cd haproxy

make all ERR=1 TARGET=linux-glibc USE_OPENSSL=1 LDFLAGS="-lprofiler"

curl -fsSL https://github.com/summerwind/h2spec/releases/download/v2.6.0/h2spec_linux_amd64.tar.gz -o h2spec.tar.gz
tar xvf h2spec.tar.gz
chmod +x h2spec

CPUPROFILE=haproxy.prof CPUPROFILESIGNAL=12 ./haproxy -f .github/h2spec.config -d &
sleep 5
killall -12 haproxy
./h2spec -Svtk -h 127.0.0.1 -p 8443
killall -12 haproxy
sleep 5

killall  haproxy

no haproxy.prof was created

ilia@fedora:~/temp/haproxy-profile$ ls -l haproxy.prof
ls: cannot access 'haproxy.prof': No such file or directory
ilia@fedora:~/temp/haproxy-profile$ 

nevermind, I've managed with "31" signal. 12 was just handled by haproxy itself