[v2,2/2] timer: support EAL functions on Windows
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Commit Message
Implemented the needed Windows eal timer functions.
Signed-off-by: Fady Bader <fady@mellanox.com>
---
lib/librte_eal/common/meson.build | 1 +
lib/librte_eal/windows/eal.c | 6 +++
lib/librte_eal/windows/eal_timer.c | 68 +++++++++++++++++++++++++++++++++
lib/librte_eal/windows/include/rte_os.h | 2 +
lib/librte_eal/windows/meson.build | 1 +
5 files changed, 78 insertions(+)
create mode 100644 lib/librte_eal/windows/eal_timer.c
Comments
On 2020-04-27 15:20 GMT+0300 Fady Bader wrote:
> Implemented the needed Windows eal timer functions.
[snip]
> +void
> +rte_delay_us_sleep(unsigned int us)
> +{
> + HANDLE timer;
> + LARGE_INTEGER li_due_time;
Here usually comes a blank line.
> + /* create waitable timer */
> + timer = CreateWaitableTimer(NULL, TRUE, NULL);
> + if (!timer) {
> + RTE_LOG_WIN32_ERR("CreateWaitableTimer()");
> + rte_errno = ENOMEM;
> + return;
> + }
> +
> + /* set us microseconds time for timer */
> + li_due_time.QuadPart = -(us * 10);
The comment is still misleading.
[snip]
> +uint64_t
> +get_tsc_freq(void)
> +{
> + uint64_t tsc_freq;
> + LARGE_INTEGER Frequency;
> +
> + QueryPerformanceFrequency(&Frequency);
> +
> + /*
> + * Mulitply by 1K to obtain the true frequency of the CPU
> + * it was noted in the MSDN "in many cases, QueryPerformanceFrequency
> + * returns the TSC frequency divided by 1024"
> + */
> + tsc_freq = ((uint64_t)Frequency.QuadPart * 1024);
> +
> + return tsc_freq;
> +}
Extended quote from MSDN:
Cases might exist where QueryPerformanceFrequency doesn't return the
actual frequency of the hardware tick generator. For example, in many
cases, QueryPerformanceFrequency returns the TSC frequency divided by
1024; and on Hyper-V, the performance counter frequency is always 10
MHz when the guest virtual machine runs under a hypervisor that
implements the hypervisor version 1.0 interface. As a result, don't
assume that QueryPerformanceFrequency will return the precise TSC
frequency.
https://docs.microsoft.com/en-us/windows/win32/sysinfo/acquiring-high-resolution-time-stamps
"In many cases" is pretty vague, we can't distinguish such cases.
Here's what I observe on my QEMU guest ("ticks" is Win32 API, "tsc" is RDTSC):
freq = 100000000 Hz # note: 100 MHz, not 10 MHz
delta (ticks) = 100401071 # Sleep(1000)
delta (secs) = 1.004011 # delta (ticks) / freq
delta (tsc) = 3460948332 # roughly CPU clock frequency
tsc / tick = 34.471229
I suggest measuring a real-time delay with rte_get_tsc_cycles() from arch/
as other EALs do when HPET is not available or configured. This is
discouraged by MSDN, but its reasons seem irrelevant for DPDK.
@@ -20,6 +20,7 @@ if is_windows
'eal_common_options.c',
'eal_common_tailqs.c',
'eal_common_thread.c',
+ 'eal_common_timer.c',
'malloc_elem.c',
'malloc_heap.c',
'rte_malloc.c',
@@ -400,6 +400,12 @@ rte_eal_init(int argc, char **argv)
return -1;
}
+ if (rte_eal_timer_init() < 0) {
+ rte_eal_init_alert("Cannot init TSC timer");
+ rte_errno = EFAULT;
+ return -1;
+ }
+
eal_thread_init_master(rte_config.master_lcore);
RTE_LCORE_FOREACH_SLAVE(i) {
new file mode 100644
@@ -0,0 +1,68 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright 2020 Mellanox Technologies, Ltd
+ */
+#include <inttypes.h>
+#include <time.h>
+
+#include <rte_windows.h>
+#include <rte_common.h>
+#include <rte_log.h>
+#include <rte_cycles.h>
+#include <rte_eal.h>
+#include <rte_errno.h>
+
+/* The frequency of the RDTSC timer resolution */
+static uint64_t eal_tsc_resolution_hz;
+
+void
+rte_delay_us_sleep(unsigned int us)
+{
+ HANDLE timer;
+ LARGE_INTEGER li_due_time;
+ /* create waitable timer */
+ timer = CreateWaitableTimer(NULL, TRUE, NULL);
+ if (!timer) {
+ RTE_LOG_WIN32_ERR("CreateWaitableTimer()");
+ rte_errno = ENOMEM;
+ return;
+ }
+
+ /* set us microseconds time for timer */
+ li_due_time.QuadPart = -(us * 10);
+ if (!SetWaitableTimer(timer, &li_due_time, 0, NULL, NULL, FALSE)) {
+ CloseHandle(timer);
+ RTE_LOG_WIN32_ERR("SetWaitableTimer()");
+ rte_errno = EINVAL;
+ return;
+ }
+ /* start wait for timer for us microseconds */
+ WaitForSingleObject(timer, INFINITE);
+ CloseHandle(timer);
+}
+
+uint64_t
+get_tsc_freq(void)
+{
+ uint64_t tsc_freq;
+ LARGE_INTEGER Frequency;
+
+ QueryPerformanceFrequency(&Frequency);
+
+ /*
+ * Mulitply by 1K to obtain the true frequency of the CPU
+ * it was noted in the MSDN "in many cases, QueryPerformanceFrequency
+ * returns the TSC frequency divided by 1024"
+ */
+ tsc_freq = ((uint64_t)Frequency.QuadPart * 1024);
+
+ return tsc_freq;
+}
+
+
+int
+rte_eal_timer_init(void)
+{
+ set_tsc_freq();
+ return 0;
+}
+
@@ -24,6 +24,8 @@ extern "C" {
#define PATH_MAX _MAX_PATH
#endif
+#define sleep(x) Sleep(1000 * (x))
+
#define strerror_r(a, b, c) strerror_s(b, c, a)
/* strdup is deprecated in Microsoft libc and _strdup is preferred */
@@ -12,6 +12,7 @@ sources += files(
'eal_memory.c',
'eal_mp.c',
'eal_thread.c',
+ 'eal_timer.c',
'getopt.c',
)