From: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
To: Stefan Hajnoczi <stefanha@gmail.com>
Cc: Avi Kivity <avi@redhat.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
LKML <linux-kernel@vger.kernel.org>, KVM <kvm@vger.kernel.org>
Subject: Re: [PATCH 3/3] KVM: perf: kvm events analysis tool
Date: Tue, 17 Jan 2012 10:37:11 +0800 [thread overview]
Message-ID: <4F14DED7.3030002@linux.vnet.ibm.com> (raw)
In-Reply-To: <CAJSP0QVxR9sYYh_Vr6ZKAU-YrWpjgL5jpiKz2zt7eJxV_kgaOg@mail.gmail.com>
On 01/16/2012 06:08 PM, Stefan Hajnoczi wrote:
> On Mon, Jan 16, 2012 at 9:32 AM, Xiao Guangrong
> <xiaoguangrong@linux.vnet.ibm.com> wrote:
>> +DESCRIPTION
>> +-----------
>> +You can analyze some crucial events and statistics with this
>> +'perf kvm-events' command.
>
> This line is very general and does not explain which events/statistics
> can be collected or how you can use that information. I suggest
> making this description more specific. Explain that this subcommand
> observers kvm.ko tracepoints and annotates/decodes them with
> additional information (this is why I would use this command and not
> raw perf record -e kvm:\*).
>
Okay.
>> + � � � { SVM_EXIT_MONITOR, � � � � � � � � � � "monitor" }, \
>> + � � � { SVM_EXIT_MWAIT, � � � � � � � � � � � "mwait" }, \
>> + � � � { SVM_EXIT_XSETBV, � � � � � � � � � � �"xsetbv" }, \
>> + � � � { SVM_EXIT_NPF, � � � � � � � � � � � � "npf" }
>
> All this copy-paste could be avoided by sharing this stuff with the
> arch/x86/kvm/ code.
>
I will try to combine them in the next version.
>> +static void exit_event_decode_key(struct event_key *key, char decode[20])
>> +{
>> + � � � const char *exit_reason = get_exit_reason(key->info, key->key);
>> +
>> + � � � memset(decode, 0, 20);
>> + � � � strncpy(decode, exit_reason, 20);
>
> This is a bad pattern to follow when using strncpy(3) because if there
> was a strlen(exit_reason) == 20 string then decode[] would not be
> NUL-terminated. Right now it's safe but it's better to just use
> strlcpy() and drop the memset(3).
>
Good point.
>> +static void mmio_event_decode_key(struct event_key *key, char decode[20])
>> +{
>> + � � � memset(decode, 0, 20);
>> + � � � sprintf(decode, "%#lx:%s", key->key,
>> + � � � � � � � key->info == KVM_TRACE_MMIO_READ ? "R" : "W");
>
> Please drop the memset and use snprintf(3) instead of sprintf(3). It
> places the NUL-terminator and ensures you don't exceed the buffer
> size.
>
> Same pattern below.
>
Will do, thanks Stefan! :)
next prev parent reply other threads:[~2012-01-17 2:47 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-16 9:30 [RFC][PATCH] KVM: perf: a smart tool to analyse kvm events Xiao Guangrong
2012-01-16 9:31 ` [PATCH 1/3] KVM: trace mmio read event properly Xiao Guangrong
2012-01-16 10:18 ` Avi Kivity
2012-01-17 2:36 ` Xiao Guangrong
2012-01-16 9:32 ` [PATCH 2/3] KVM: improve trace events of vmexit/mmio/ioport Xiao Guangrong
2012-01-16 9:38 ` Avi Kivity
2012-01-17 2:28 ` Xiao Guangrong
2012-01-17 11:55 ` Marcelo Tosatti
2012-01-17 17:31 ` David Ahern
2012-01-18 2:32 ` Xiao Guangrong
2012-01-18 5:34 ` David Ahern
2012-01-24 12:44 ` Avi Kivity
2012-01-16 9:32 ` [PATCH 3/3] KVM: perf: kvm events analysis tool Xiao Guangrong
2012-01-16 10:04 ` Avi Kivity
2012-01-17 2:30 ` Xiao Guangrong
2012-01-24 12:49 ` Avi Kivity
2012-01-16 10:08 ` Stefan Hajnoczi
2012-01-17 2:37 ` Xiao Guangrong [this message]
2012-01-17 11:59 ` Marcelo Tosatti
2012-01-24 12:51 ` Avi Kivity
2012-01-16 10:11 ` [RFC][PATCH] KVM: perf: a smart tool to analyse kvm events Avi Kivity
2012-01-17 2:30 ` Xiao Guangrong
2012-01-16 22:53 ` David Ahern
2012-01-17 2:41 ` Xiao Guangrong
2012-01-17 4:49 ` David Ahern
2012-02-09 9:06 [PATCH v4 0/3] KVM: perf: kvm events analysis tool Xiao Guangrong
2012-02-09 9:09 ` [PATCH 3/3] " Xiao Guangrong
2012-02-13 3:04 ` David Ahern
2012-02-13 5:00 ` Xiao Guangrong
2012-02-20 23:47 ` David Ahern
2012-02-21 3:52 ` Xiao Guangrong
2012-02-21 4:58 ` David Ahern
2012-02-27 4:57 ` Xiao Guangrong
2012-02-13 5:32 David Ahern
2012-02-13 10:06 ` Xiao Guangrong
2012-02-13 15:52 ` David Ahern
2012-02-16 4:59 ` Xiao Guangrong
2012-02-16 5:05 ` David Ahern
2012-02-16 5:33 ` Xiao Guangrong
2012-02-16 16:35 ` Arnaldo Carvalho de Melo
2012-03-06 8:55 [PATCH v5 0/3] " Xiao Guangrong
2012-03-06 8:58 ` [PATCH 3/3] " Xiao Guangrong
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