New graph from today. fsetxattr seems to take a lot of CPU too. Am 09.11.2012 11:09, schrieb Stefan Priebe - Profihost AG:
Disabling the logging with: debug lockdep = 0/0 debug context = 0/0 debug crush = 0/0 debug buffer = 0/0 debug timer = 0/0 debug journaler = 0/0 debug osd = 0/0 debug optracker = 0/0 debug objclass = 0/0 debug filestore = 0/0 debug journal = 0/0 debug ms = 0/0 debug monc = 0/0 debug tp = 0/0 debug auth = 0/0 debug finisher = 0/0 debug heartbeatmap = 0/0 debug perfcounter = 0/0 debug asok = 0/0 debug throttle = 0/0 reduced the CPU load about 50% ! So each OSD process now takes only one whole 3.6Ghz core instead of two. Have you looked at my latest profile graph with disabled debug options? Greets, Stefan Am 08.11.2012 17:06, schrieb Mark Nelson:On 11/08/2012 09:45 AM, Stefan Priebe - Profihost AG wrote:Am 08.11.2012 16:01, schrieb Sage Weil:On Thu, 8 Nov 2012, Stefan Priebe - Profihost AG wrote:Is there any way to find out why a ceph-osd process takes around 10 times more load on rand 4k writes than on 4k reads?Something like perf or oprofile is probably your best bet. perf can be tedious to deploy, depending on where your kernel is coming from. oprofile seems to be deprecated, although I've had good results with it in the past.I've recorded 10s with perf - it is now a 300MB perf.data file. Sadly i've no idea what todo with it next.Pour yourself a stiff drink! (haha!) Try just doing a "perf report" in the directory where you've got the data file. Here's a nice tutorial: https://perf.wiki.kernel.org/index.php/Tutorial Also, if you see missing symbols you might benefit by chowning the file to root and running perf report as root. If you still see missing symbols, you may want to just give up and try sysprof.would love to see where the CPU is spending most of it's time. This is on current master?YesI expect there are still some low-hanging fruit that can bring CPU utilization down (or even boost iops).Would be great to find them. Stefan -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html-- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html-- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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