From: Sergio Gonzalez Monroy <sergio.gonzalez.monroy@intel.com>
To: dev@dpdk.org
Subject: [dpdk-dev] [PATCH 1/2] eal: use sysctl in BSD to set TSC freq
Date: Thu, 20 Nov 2014 14:06:58 +0000 [thread overview]
Message-ID: <1416492419-11957-2-git-send-email-sergio.gonzalez.monroy@intel.com> (raw)
In-Reply-To: <1416492419-11957-1-git-send-email-sergio.gonzalez.monroy@intel.com>
BSD provides the TSC frequency value through sysctl.
Signed-off-by: Sergio Gonzalez Monroy <sergio.gonzalez.monroy@intel.com>
---
lib/librte_eal/bsdapp/eal/eal_timer.c | 46 ++++++++++++++++++++---------------
1 file changed, 27 insertions(+), 19 deletions(-)
diff --git a/lib/librte_eal/bsdapp/eal/eal_timer.c b/lib/librte_eal/bsdapp/eal/eal_timer.c
index fd800b9..67da167 100644
--- a/lib/librte_eal/bsdapp/eal/eal_timer.c
+++ b/lib/librte_eal/bsdapp/eal/eal_timer.c
@@ -41,6 +41,8 @@
#include <sys/mman.h>
#include <sys/queue.h>
#include <pthread.h>
+#include <sys/types.h>
+#include <sys/sysctl.h>
#include <errno.h>
#include <rte_common.h>
@@ -241,29 +243,34 @@ rte_eal_hpet_init(int make_default)
#endif
static int
-set_tsc_freq_from_clock(void)
+set_tsc_freq_from_sysctl(void)
{
-#ifdef CLOCK_MONOTONIC_RAW
-#define NS_PER_SEC 1E9
+ size_t sz;
+ int tmp;
- struct timespec sleeptime = {.tv_nsec = 5E8 }; /* 1/2 second */
+ sz = sizeof(tmp);
+ tmp = 0;
- struct timespec t_start, t_end;
+ if (sysctlbyname("kern.timecounter.smp_tsc", &tmp, &sz, NULL, 0))
+ RTE_LOG(WARNING, EAL, "%s\n", strerror(errno));
+ else if (tmp != 1)
+ RTE_LOG(WARNING, EAL, "TSC is not safe to use in SMP mode\n");
- if (clock_gettime(CLOCK_MONOTONIC_RAW, &t_start) == 0) {
- uint64_t ns, end, start = rte_rdtsc();
- nanosleep(&sleeptime,NULL);
- clock_gettime(CLOCK_MONOTONIC_RAW, &t_end);
- end = rte_rdtsc();
- ns = ((t_end.tv_sec - t_start.tv_sec) * NS_PER_SEC);
- ns += (t_end.tv_nsec - t_start.tv_nsec);
+ tmp = 0;
- double secs = (double)ns/NS_PER_SEC;
- eal_tsc_resolution_hz = (uint64_t)((end - start)/secs);
- return 0;
+ if (sysctlbyname("kern.timecounter.invariant_tsc", &tmp, &sz, NULL, 0))
+ RTE_LOG(WARNING, EAL, "%s\n", strerror(errno));
+ else if (tmp != 1)
+ RTE_LOG(WARNING, EAL, "TSC is not invariant\n");
+
+ sz = sizeof(eal_tsc_resolution_hz);
+
+ if (sysctlbyname("machdep.tsc_freq", &eal_tsc_resolution_hz, &sz, NULL, 0)) {
+ RTE_LOG(WARNING, EAL, "%s\n", strerror(errno));
+ return -1;
}
-#endif
- return -1;
+
+ return 0;
}
static void
@@ -277,10 +284,11 @@ set_tsc_freq_fallback(void)
sleep(1);
eal_tsc_resolution_hz = rte_rdtsc() - start;
}
+
/*
* This function measures the TSC frequency. It uses a variety of approaches.
*
- * 1. If kernel provides CLOCK_MONOTONIC_RAW we use that to tune the TSC value
+ * 1. Read the TSC frequency value provided by the kernel
* 2. If kernel does not provide that, and we have HPET support, tune using HPET
* 3. Lastly, if neither of the above can be used, just sleep for 1 second and
* tune off that, printing a warning about inaccuracy of timing
@@ -288,7 +296,7 @@ set_tsc_freq_fallback(void)
static void
set_tsc_freq(void)
{
- if (set_tsc_freq_from_clock() < 0)
+ if (set_tsc_freq_from_sysctl() < 0)
set_tsc_freq_fallback();
RTE_LOG(INFO, EAL, "TSC frequency is ~%"PRIu64" KHz\n",
--
2.1.0
next prev parent reply other threads:[~2014-11-20 13:56 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-20 14:06 [dpdk-dev] [PATCH 0/2] BSD timer cleanup/update Sergio Gonzalez Monroy
2014-11-20 14:06 ` Sergio Gonzalez Monroy [this message]
2014-11-20 14:06 ` [dpdk-dev] [PATCH 2/2] eal: Remove unused HPET support from FreeBSD Sergio Gonzalez Monroy
2014-11-27 11:57 ` [dpdk-dev] [PATCH 0/2] BSD timer cleanup/update Thomas Monjalon
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1416492419-11957-2-git-send-email-sergio.gonzalez.monroy@intel.com \
--to=sergio.gonzalez.monroy@intel.com \
--cc=dev@dpdk.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).