From: Thomas Monjalon <thomas.monjalon@6wind.com>
Date: Thu, 31 May 2012 17:00:31 +0000 (+0200)
Subject: timer: get TSC frequency from /proc/cpuinfo
X-Git-Tag: spdx-start~10955
X-Git-Url: http://git.droids-corp.org/?a=commitdiff_plain;h=da6fd0759cbeb5fc14991a79e40105b9f6b99059;p=dpdk.git

timer: get TSC frequency from /proc/cpuinfo

TSC frequency was guessed by reading CLOCK_MONOTONIC_RAW or sleeping 1 sec.
Now, read frequency from cpuinfo first.
Keep other methods as fallbacks.

Signed-off-by: Thomas Monjalon <thomas.monjalon@6wind.com>
Acked-by: Ivan Boule <ivan.boule@6wind.com>
---

diff --git a/lib/librte_eal/linuxapp/eal/eal_timer.c b/lib/librte_eal/linuxapp/eal/eal_timer.c
index 64566d143d..1d10457b8d 100644
--- a/lib/librte_eal/linuxapp/eal/eal_timer.c
+++ b/lib/librte_eal/linuxapp/eal/eal_timer.c
@@ -278,6 +278,35 @@ check_tsc_flags(void)
 	fclose(stream);
 }
 
+static int
+set_tsc_freq_from_cpuinfo(void)
+{
+	char line[256];
+	FILE *stream;
+	double dmhz;
+
+	stream = fopen("/proc/cpuinfo", "r");
+	if (!stream) {
+		RTE_LOG(WARNING, EAL, "WARNING: Unable to open /proc/cpuinfo\n");
+		return -1;
+	}
+
+	while (fgets(line, sizeof line, stream)) {
+		if (sscanf(line, "cpu MHz\t: %lf", &dmhz) == 1) {
+			eal_tsc_resolution_hz = (uint64_t)(dmhz * 1000000UL);
+			break;
+		}
+	}
+
+	fclose(stream);
+
+	if (!eal_tsc_resolution_hz) {
+		RTE_LOG(WARNING, EAL, "WARNING: Cannot read CPU clock from cpuinfo\n");
+		return -1;
+	}
+	return 0;
+}
+
 static int
 set_tsc_freq_from_clock(void)
 {
@@ -326,8 +355,9 @@ set_tsc_freq_fallback(void)
 static void
 set_tsc_freq(void)
 {
-	if (set_tsc_freq_from_clock() < 0)
-		set_tsc_freq_fallback();
+	if (set_tsc_freq_from_cpuinfo() < 0 &&
+	    set_tsc_freq_from_clock() < 0)
+	    set_tsc_freq_fallback();
 
 	RTE_LOG(INFO, EAL, "TSC frequency is ~%"PRIu64" KHz\n",
 			eal_tsc_resolution_hz/1000);