Messages in this thread | | | From | "Metzger, Markus T" <> | Date | Fri, 7 Aug 2009 12:51:04 +0100 | Subject | RE: [patch] x86, perf_counter, bts: add bts to perf_counter |
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>-----Original Message----- >From: Peter Zijlstra [mailto:a.p.zijlstra@chello.nl] >Sent: Friday, August 07, 2009 1:45 PM >To: Metzger, Markus T >Cc: linux-kernel@vger.kernel.org; mingo@elte.hu; tglx@linutronix.de; hpa@zytor.com; >markus.t.metzger@gmail.com; oleg@redhat.com >Subject: Re: [patch] x86, perf_counter, bts: add bts to perf_counter > >On Fri, 2009-08-07 at 09:22 +0200, Markus Metzger wrote: >> @@ -721,9 +903,13 @@ static int __hw_perf_counter_init(struct >> err = 0; >> if (!atomic_inc_not_zero(&active_counters)) { >> mutex_lock(&pmc_reserve_mutex); >> - if (atomic_read(&active_counters) == 0 && !reserve_pmc_hardware()) >> - err = -EBUSY; >> - else >> + if (atomic_read(&active_counters) == 0) { >> + if (!reserve_pmc_hardware()) >> + err = -EBUSY; >> + else >> + reserve_bts_hardware(); >> + } >> + if (!err) >> atomic_inc(&active_counters); >> mutex_unlock(&pmc_reserve_mutex); >> } > >You loose the reserve_bts_hardware() error case there.
That had been intentional since I consider BTS somewhat optional. In case it is not available or fails to initialize, e.g. out of memory, we fall back to normal profiling.
Now that I think about it again, I guess that's not what a (debugger) user would expect. An error might be more appropriate in that case.
I'll change it.
thanks and regards, markus.
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