linux-kernel - Re: [PATCH] perf: change samples type to unsigned long long

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Message-ID: <20151002191059.GA20515@kernel.org>
Date:	Fri, 2 Oct 2015 16:10:59 -0300
From:	Arnaldo Carvalho de Melo <acme@...nel.org>
To:	Yang Shi <yang.shi@...aro.org>
Cc:	linux-kernel@...r.kernel.org, linaro-kernel@...ts.linaro.org
Subject: Re: [PATCH] perf: change samples type to unsigned long long

Em Fri, Oct 02, 2015 at 04:08:38PM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Tue, Sep 29, 2015 at 02:49:43PM -0700, Yang Shi escreveu:
> > When run "perf record -e", the number of samples showed up is wrong on some
> > 32 bit systems, i.e. powerpc and arm.
> > 
> > For example, run the below commands on 32 bit powerpc:
> > 
> > perf probe -x /lib/libc.so.6 malloc
> > perf record -e probe_libc:malloc -a ls
> > perf.data
> > [ perf record: Woken up 1 times to write data ]
> > [ perf record: Captured and wrote 0.036 MB perf.data (13829241621624967218 samples) ]
> > 
> > Actually, "perf script" just shows 21 samples. The number of samples is also
> > absurd since samples is long type, but it is printed as PRIu64.
> > 
> > Build test is run on x86-64, x86, aarch64, arm, mips, ppc and ppc64.
> 
> Sure?
> 
>   AR       /tmp/build/perf/libperf.a
> builtin-record.c: In function ‘__cmd_record’:
> builtin-record.c:689:12: error: comparison between signed and unsigned
> integer expressions [-Werror=sign-compare]

You missed something important, I am fixing this and applying your
patch:

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 974065f8ce80..24ace2f318c1 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -667,7 +667,7 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
 
 	auxtrace_snapshot_enabled = 1;
 	for (;;) {
-		int hits = rec->samples;
+		unsigned long long hits = rec->samples;
 
 		if (record__mmap_read_all(rec) < 0) {
 			auxtrace_snapshot_enabled = 0;
--
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