Messages in this thread | | | Date | Thu, 5 Mar 2009 11:07:48 +0100 | From | Ingo Molnar <> | Subject | Re: [RFC PATCH] perfcounters: provide expansion room in the ABI |
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* Paul Mackerras <paulus@samba.org> wrote:
> Ingo Molnar wrote: > > > > git://git.kernel.org/pub/scm/linux/kernel/git/paulus/perfcounters.git rfc > > > > > > include/linux/perf_counter.h | 12 +++++++++--- > > > include/linux/syscalls.h | 2 +- > > > kernel/perf_counter.c | 10 +++++++--- > > > 3 files changed, 17 insertions(+), 7 deletions(-) > > > > Pulled into tip:perfcounters/core, thanks Paul! > > Actually, I goofed slightly. In this bit of the patch: > > @@ -80,10 +81,15 @@ struct perf_counter_hw_event { > exclude_user : 1, /* don't count user */ > exclude_kernel : 1, /* ditto kernel */ > exclude_hv : 1, /* ditto hypervisor */ > + exclude_idle : 1, /* don't count when idle */ > > - __reserved_1 : 23; > + __reserved_1 : 55; > + > > the 55 should have been 54 if we want those bitfields to > occupy 64 bits. With 55 there, __reserved_1 will go in the > next 64-bit quadword (x86-speak, or doubleword in > powerpc-speak). > > Do you think that's worth changing? If so I'll do a commit > changing the 55 to 54.
How about extending it to 118 instead? The creation of a counter is a slow path in any case.
Ingo
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