Use trace-cmd. It reads the per cpu files and sorts later -- Steve
On August 27, 2014 4:50:38 AM GMT-04:00, Dmitry Monakhov <dmonak...@openvz.org> wrote: > >I have tried to use tracing on host with 32cpus, but it is appeared >that performance is horrible. >dd if=/sys/kernel/debug/tracing/trace_pipe of=tmpfs/t3.log bs=1M >0+21268 records in >0+21267 records out >85701248 bytes (86 MB) copied, 26.1424 s, 3.3 MB/s >0+25706 records in >0+25705 records out >103600749 bytes (104 MB) copied, 31.6595 s, 3.3 MB/s >0+59204 records in >0+59203 records out >238746128 bytes (239 MB) copied, 73.4347 s, 3.3 MB/s >Since I've collected ~3Gb of data this takes a lot of time to >simply copy from kernel to tmpfs. > >AFAIU this happen due to sub-optimal sorting procedure >__find_next_entry >Each time it walks each cpu and pick the one with smallest timestamp. >This can be optimized simply by fetching N-entries at the time. Are >there any plans to implement that? > >BTW:What is the most convenient way fetch big data from traces? >One of possible way is to dump per-cpu traces(20Mb/s in my case) and >then merge files according to timestamp -- Sent from my Android device with K-9 Mail. Please excuse my brevity. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
