From: Joe Korty <joe.korty@ccur.com>
To: mingo@elte.hu
Cc: linux-kernel@vger.kernel.org
Subject: [PATCH] lockstat - fix numerical output rounding error
Date: Mon, 25 Aug 2008 17:15:33 -0400 [thread overview]
Message-ID: <20080825211533.GA27943@tsunami.ccur.com> (raw)
Fix rounding error in /proc/lock_stat numerical output.
On occasion the two digit fractional part contains the three
digit value '100'. This is due to a bug in the rounding algorithm
which pushes values in the range '95..99' to '100' rather than
to '00' + an increment to the integer part. For example,
- 123456.100 old display
+ 123457.00 new display
Index: 2.6.26/kernel/lockdep_proc.c
===================================================================
--- 2.6.26.orig/kernel/lockdep_proc.c 2008-07-13 17:51:29.000000000 -0400
+++ 2.6.26/kernel/lockdep_proc.c 2008-08-25 16:58:04.000000000 -0400
@@ -406,8 +406,9 @@
{
unsigned long rem;
+ nr += 5; /* for display rounding */
rem = do_div(nr, 1000); /* XXX: do_div_signed */
- snprintf(buf, bufsiz, "%lld.%02d", (long long)nr, ((int)rem+5)/10);
+ snprintf(buf, bufsiz, "%lld.%02d", (long long)nr, (int)rem/10);
}
static void seq_time(struct seq_file *m, s64 time)
next reply other threads:[~2008-08-25 21:49 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-08-25 21:15 Joe Korty [this message]
2008-08-26 8:37 ` [PATCH] lockstat - fix numerical output rounding error Ingo Molnar
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