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Date: Mon, 11 Dec 2017 15:25:47 -0300
From: Arnaldo Carvalho de Melo <acme@...nel.org>
To: Paul Clarke <pc@...ibm.com>
Cc: Masami Hiramatsu <mhiramat@...nel.org>,
bhargavb <bhargavaramudu@...il.com>,
linux-kernel@...r.kernel.org,
Ravi Bangoria <ravi.bangoria@...ux.vnet.ibm.com>,
linux-rt-users@...r.kernel.org, linux-perf-users@...r.kernel.org
Subject: Re: [PATCH v2 2/5] perf-probe: Cut off the version suffix from event
name
Em Fri, Dec 08, 2017 at 08:49:46AM -0600, Paul Clarke escreveu:
>
>
> On 12/07/2017 09:01 PM, Masami Hiramatsu wrote:
> > On Thu, 7 Dec 2017 10:34:51 -0600
> > Paul Clarke <pc@...ibm.com> wrote:
> >> On 12/07/2017 01:20 AM, Masami Hiramatsu wrote:
> >>> Cut off the version suffix (e.g. @GLIBC_2.2.5 etc.) from
> >>> automatic generated event name. This fixes wildcard event
> >>> adding like below case;
> >>>
> >>> =====
> >>> # perf probe -x /lib64/libc-2.25.so malloc*
> >>> Internal error: "malloc_get_state@...BC_2" is wrong event name.
> >>> Error: Failed to add events.
> >>> =====
> >>>
> >>> This failure was caused by a versioned suffix symbol.
> >>> With this fix, perf probe automatically cuts the
> >>> suffix after @ as below.
> >>>
> >>> =====
> >>> # ./perf probe -x /lib64/libc-2.25.so malloc*
> >>> Added new events:
> >>> probe_libc:malloc_printerr (on malloc* in /usr/lib64/libc-2.25.so)
> >>> probe_libc:malloc_consolidate (on malloc* in /usr/lib64/libc-2.25.so)
> >>> probe_libc:malloc_check (on malloc* in /usr/lib64/libc-2.25.so)
> >>> probe_libc:malloc_hook_ini (on malloc* in /usr/lib64/libc-2.25.so)
> >>> probe_libc:malloc (on malloc* in /usr/lib64/libc-2.25.so)
> >>> probe_libc:malloc_trim (on malloc* in /usr/lib64/libc-2.25.so)
> >>> probe_libc:malloc_usable_size (on malloc* in /usr/lib64/libc-2.25.so)
> >>> probe_libc:malloc_stats (on malloc* in /usr/lib64/libc-2.25.so)
> >>> probe_libc:malloc_info (on malloc* in /usr/lib64/libc-2.25.so)
> >>> probe_libc:mallochook (on malloc* in /usr/lib64/libc-2.25.so)
> >>> probe_libc:malloc_get_state (on malloc* in /usr/lib64/libc-2.25.so)
> >>> probe_libc:malloc_set_state (on malloc* in /usr/lib64/libc-2.25.so)
> >>>
> >>> You can now use it in all perf tools, such as:
> >>>
> >>> perf record -e probe_libc:malloc_set_state -aR sleep 1
> >>>
> >>> =====
> >>
> >> I think this will still fall over for a case where there are multiple versions of the same base symbol, like:
> >>
> >> $ nm /lib64/libc.so.6 | egrep ' sched_getaffinity'
> >> 0000000000134430 T sched_getaffinity@...BC_2.3.3
> >> 00000000000dcf00 T sched_getaffinity@@GLIBC_2.3.4
> >
> > No, in that case perf probe adds number suffix (_1, _2...) for new events :)
> >
> > This feature (number suffix) is anyway required for the case that inlined
> > function is spreaded in multiple places. I think this is natural for perf probe.
>
> I can live with that.
>
> Is the versioning tag retained for display with "perf probe -l" display, so the probe points can be distinguished?
>
> In other words, will one see:
> # perf probe -l
> probe_libc:sched_getaffinity (on sched_getaffinity@...BC_2.3.3 in /usr/lib64/libc-2.17.so)
> probe_libc:sched_getaffinity_1 (on sched_getaffinity@@GLIBC_2.3.4 in /usr/lib64/libc-2.17.so)
> or
> # perf probe -l
> probe_libc:sched_getaffinity (on sched_getaffinity in /usr/lib64/libc-2.17.so)
> probe_libc:sched_getaffinity_1 (on sched_getaffinity in /usr/lib64/libc-2.17.so)
[root@...et ~]# perf probe -x /lib64/libc-2.25.so malloc*
Added new events:
probe_libc:malloc_printerr (on malloc* in /usr/lib64/libc-2.25.so)
probe_libc:malloc_consolidate (on malloc* in /usr/lib64/libc-2.25.so)
probe_libc:malloc_check (on malloc* in /usr/lib64/libc-2.25.so)
probe_libc:malloc_hook_ini (on malloc* in /usr/lib64/libc-2.25.so)
probe_libc:malloc (on malloc* in /usr/lib64/libc-2.25.so)
probe_libc:malloc_trim (on malloc* in /usr/lib64/libc-2.25.so)
probe_libc:malloc_usable_size (on malloc* in /usr/lib64/libc-2.25.so)
probe_libc:malloc_stats (on malloc* in /usr/lib64/libc-2.25.so)
probe_libc:malloc_info (on malloc* in /usr/lib64/libc-2.25.so)
probe_libc:mallochook (on malloc* in /usr/lib64/libc-2.25.so)
probe_libc:malloc_get_state (on malloc* in /usr/lib64/libc-2.25.so)
probe_libc:malloc_set_state (on malloc* in /usr/lib64/libc-2.25.so)
You can now use it in all perf tools, such as:
perf record -e probe_libc:malloc_set_state -aR sleep 1
[root@...et ~]# perf probe -l
probe_libc:malloc (on 0xd22a6973 in /usr/lib64/libc-2.25.so)
probe_libc:malloc_check (on 0x25db6f5a in /usr/lib64/libc-2.25.so)
probe_libc:malloc_consolidate (on 0x88f7c44a in /usr/lib64/libc-2.25.so)
probe_libc:malloc_get_state (on 0xdd38eca7 in /usr/lib64/libc-2.25.so)
probe_libc:malloc_hook_ini (on 0x8de2b533 in /usr/lib64/libc-2.25.so)
probe_libc:malloc_info (on 0x8b327bde in /usr/lib64/libc-2.25.so)
probe_libc:malloc_printerr (on 0x8fff087c in /usr/lib64/libc-2.25.so)
probe_libc:malloc_set_state (on 0x861940e6 in /usr/lib64/libc-2.25.so)
probe_libc:malloc_stats (on 0x51fa3cdc in /usr/lib64/libc-2.25.so)
probe_libc:malloc_trim (on 0xa9fa4e43 in /usr/lib64/libc-2.25.so)
probe_libc:malloc_usable_size (on 0xceb5e090 in /usr/lib64/libc-2.25.so)
probe_libc:mallochook (on 0x6ebc00f5 in /usr/lib64/libc-2.25.so)
[root@...et ~]#
[acme@...et perf]$ nm /lib64/libc-2.25.so | grep malloc_get_state
0000000000151ba0 T malloc_get_state@...BC_2.2.5
[acme@...et perf]$
For your example it finds two symbols, adds two but I couldn't find a
simple way of mapping one to the other, would be nice if 'perf probe -l'
showed them like 'nm' does.
[root@...et ~]# nm /lib64/libc-2.25.so | grep ' sched_getaffinity'
0000000000151cd0 T sched_getaffinity@...BC_2.3.3
00000000000f3c10 T sched_getaffinity@@GLIBC_2.3.4
[root@...et ~]#
[root@...et ~]# perf probe -x /lib64/libc-2.25.so sched_getaffinity*
Added new events:
probe_libc:sched_getaffinity (on sched_getaffinity* in /usr/lib64/libc-2.25.so)
probe_libc:sched_getaffinity_1 (on sched_getaffinity* in /usr/lib64/libc-2.25.so)
You can now use it in all perf tools, such as:
perf record -e probe_libc:sched_getaffinity_1 -aR sleep 1
[root@...et ~]# perf probe -l
probe_libc:sched_getaffinity (on 0x5fd95e7c in /usr/lib64/libc-2.25.so)
probe_libc:sched_getaffinity_1 (on 0xd8d51601 in /usr/lib64/libc-2.25.so)
[root@...et ~]#
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