Messages in this thread | | | Date | Thu, 5 Dec 2013 11:43:13 -0800 | Subject | Re: [RFC PATCH tip 0/5] tracing filters with BPF | From | Alexei Starovoitov <> |
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On Thu, Dec 5, 2013 at 8:11 AM, Frank Ch. Eigler <fche@redhat.com> wrote: > > ast wrote: > >>>[...] >> Did simple ktap test with 1M alloc_skb/kfree_skb toy test from earlier email: >> trace skb:kfree_skb { >> if (arg2 == 0x100) { >> printf("%x %x\n", arg1, arg2) >> } >> } >> [...] > > For reference, you might try putting systemtap into the performance > comparison matrix too: > > # stap -e 'probe kernel.trace("kfree_skb") { > if ($location == 0x100 /* || $location == 0x200 etc. */ ) { > printf("%x %x\n", $skb, $location) > } > }'
stap with one 'if': 1M skb alloc/free 200696 (usecs) stap with 10 'if': 1M skb alloc/free 202135 (usecs)
so systemtap entry overhead is a bit higher than bpf and extra if-s show the same progression as expected.
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