From mboxrd@z Thu Jan 1 00:00:00 1970 From: Len Brown Subject: [PATCH 6/7] tools/power turbostat: prevent infinite loop on migration error path Date: Wed, 14 Nov 2012 15:43:23 -0500 Message-ID: <883d5d681f426eb42ad65d805cfc138dea986b6c.1352925508.git.len.brown@intel.com> References: <1352925804-6746-1-git-send-email-lenb@kernel.org> Reply-To: Len Brown Return-path: In-Reply-To: <1352925804-6746-1-git-send-email-lenb@kernel.org> In-Reply-To: <39300ffb9b6666714c60735cf854e1280e4e75f4.1352925508.git.len.brown@intel.com> References: <39300ffb9b6666714c60735cf854e1280e4e75f4.1352925508.git.len.brown@intel.com> Sender: linux-kernel-owner@vger.kernel.org To: linux-pm@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Len Brown List-Id: linux-pm@vger.kernel.org From: Len Brown Turbostat assumed if it can't migrate to a CPU, then the CPU must have gone off-line and turbostat should re-initialize with the new topology. But if turbostat can not migrate because it is restricted by a cpuset, then it will fail to migrate even after re-initialization, resulting in an infinite loop. Spit out a warning when we can't migrate and endure only 2 re-initialize cycles in a row before giving up and exiting. Signed-off-by: Len Brown --- tools/power/x86/turbostat/turbostat.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c index 3c063a0..77e76b1 100644 --- a/tools/power/x86/turbostat/turbostat.c +++ b/tools/power/x86/turbostat/turbostat.c @@ -656,8 +656,10 @@ int get_counters(struct thread_data *t, struct core_data *c, struct pkg_data *p) { int cpu = t->cpu_id; - if (cpu_migrate(cpu)) + if (cpu_migrate(cpu)) { + fprintf(stderr, "Could not migrate to CPU %d\n", cpu); return -1; + } t->tsc = rdtsc(); /* we are running on local CPU of interest */ @@ -1088,15 +1090,22 @@ int mark_cpu_present(int cpu) void turbostat_loop() { int retval; + int restarted = 0; restart: + restarted++; + retval = for_all_cpus(get_counters, EVEN_COUNTERS); if (retval < -1) { exit(retval); } else if (retval == -1) { + if (restarted > 1) { + exit(retval); + } re_initialize(); goto restart; } + restarted = 0; gettimeofday(&tv_even, (struct timezone *)NULL); while (1) { -- 1.8.0