Hi +elspuddo thanks for this demo. It did educate me a little bit on the mental process of reading an strace capture file. It's something I have been trying to learn for years. This was useful. I need to see more of these though. Thanks!
Very helpful, although I ended up greping for my IP address rather than the PID but left me with a problem ... strace'ing the php script I'm troubleshooting shows the script outputs to the console in around 0.02 seconds ... but all the test I run over the internet show a TTFB of around 0.8 to 0.9 seconds - I've ruled out the network (pings are sub 20ms) and the server load average is very low - any ideas of how to troubleshoot this further?
you can specify the file to cut instead of using cat and redirecting the output (and by using tail instead of head I don't have to type that one extra 'r': cut -c12-16 /tmp/output | sort -n | tail very cool demo though - I'd no idea about the -s argument that strace has - thank you!
Glad you liked it! It's amazing that folks are still getting something out of a 10 year old video. I continue to employ the "useless use of a cat" paradigm simply because I like pipes, and I find the explicit cat satisfying.
If i understand well at 3:42, if we didn't have dual stack and IPv6 support we would be unable to find the corresponding httpd PID? strange! It is only possible to do that by pushing the Timeout of Apache. in httpd.conf you can put Timeout 8000 & RequestReadTimeout Header=8000 Body=8000
Top quality demonstration. Thank You!
Hi +elspuddo thanks for this demo. It did educate me a little bit on the mental process of reading an strace capture file. It's something I have been trying to learn for years. This was useful. I need to see more of these though. Thanks!
I'll have to apply this to Apache and Perl now. Good job on the video and thanks.
I really enjoy viewing this video!
Very informative - never used strace before so I learned a lot!
very thorough and "extreme" web debugging. Might come in handy one day.
Awesome demo, thanks! What's the font? Where can I download the background image from?
sort -k2 -rn /tmp/output | head :) saved TWO kittehs!
Great and informative video, many thanks for your effort!
Yes, so glad you're making more...
Simply awesome video!
I wonder if its possible to use STRACE to see if a process is trying to delete files/folders...
Damn this is interesting, I'm going to watch this later when I understand these topics better (especially Unix networking stuff).
This was very useful, thank you.
Amazing explanation! My respect o/
awesome. thank you sir!
This is amazing! Thanks for sharing it!
Cool, at 11:00 you just confirmed why my FOG servers interface without internet is slow-ish: DNS.
video is very informative. please turn your volume up though :)
Did you bump up the Apache timeouts? IIRC you dont typically get that long to look for it.
Very helpful, although I ended up greping for my IP address rather than the PID but left me with a problem ... strace'ing the php script I'm troubleshooting shows the script outputs to the console in around 0.02 seconds ... but all the test I run over the internet show a TTFB of around 0.8 to 0.9 seconds - I've ruled out the network (pings are sub 20ms) and the server load average is very low - any ideas of how to troubleshoot this further?
Excellent!
suuuubscribed... very awesome demo.. thanks!
top notch! thank you very much!
Simply ... Amaaaaaaaazing ^____^
you can specify the file to cut instead of using cat and redirecting the output (and by using tail instead of head I don't have to type that one extra 'r':
cut -c12-16 /tmp/output | sort -n | tail
very cool demo though - I'd no idea about the -s argument that strace has - thank you!
Glad you liked it! It's amazing that folks are still getting something out of a 10 year old video. I continue to employ the "useless use of a cat" paradigm simply because I like pipes, and I find the explicit cat satisfying.
If i understand well at 3:42, if we didn't have dual stack and IPv6 support we would be unable to find the corresponding httpd PID? strange! It is only possible to do that by pushing the Timeout of Apache. in httpd.conf you can put Timeout 8000 & RequestReadTimeout Header=8000 Body=8000
What are you using as your terminal? I'd love to know what you did to rename your open windows and scroll through them in a list.
man screen :)
That's not the terminal doing that, it's GNU Screen.
Does this not work with php-fpm and per site pools? I get the http worker pid but it doesn't match up to any actual pids on the system
Is it possible to strace all the processes for a specific call?
Why doesn't this command work for me lsof -p `pidof telnet`? I'm use Debian Wheezy.
Does your system have the "pidof" command? You can usually check by running which pidof
Any reason why this command doesn't work on my machine?
root@master:~# lsof -p `pidof telnet`
lsof: no process ID specified
lsof 4.81
Excellent technique. Sadly I'm still a vi holdout.