Messages in this thread | | | From | Vaibhav Nagarnaik <> | Date | Wed, 28 Mar 2012 20:02:54 -0700 | Subject | Re: [PATCH 4/6] trace: trace syscall in its handler not from ptrace handler |
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On Wed, Mar 28, 2012 at 7:43 PM, H. Peter Anvin <hpa@zytor.com> wrote: > But instead you add a penalty for every syscall, even if tracing is > disabled. Not cool.
I just ran a small test binary which calls syscall(SYS_getuid) in a tight loop and calculates the latency per syscall.
Without my patch: it is 70 ns/call With my patch: it is 83 ns/call
So yes, it does add a bit of latency to the syscall even if tracing is disabled. I wonder if I can change the redirection function so that it doesn't add so much latency.
But if it doesn't seem to help, then I will not push this patch.
Vaibhav Nagarnaik -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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