Hi Derik,
The Linux service clock_gettime() returns a structure
with seconds and nanoseconds and you are retuning the
number of nanoseconds from QueryPerformanceCounter().
Doesn't that imply that the rate of the performance
counter is 1 ns? Does this allow you to remove the
calibration code? Depending on the clock source
used by clock_gettime(), there may be large jumps
in the number of ns. You can use clock_getres() to
see if the resolution is acceptable. It looks
like clock_gettime() optionally supports other time
sources that may be based on features such like TSC
and those may require calibration.
Mike
> -----Original Message-----
> From: devel@edk2.groups.io <devel@edk2.groups.io> On
> Behalf Of Lin, Derek (HPS SW)
> Sent: Wednesday, January 29, 2020 11:12 PM
> To: derek.l...@hpe.com; devel@edk2.groups.io
> Cc: Justen, Jordan L <jordan.l.jus...@intel.com>;
> af...@apple.com; Ni, Ray <ray...@intel.com>; Kitty Chen
> <kitty.c...@hpe.com>
> Subject: [edk2-devel] [PATCH] EmulatorPkg: TimerLib
> QueryPerformance functions
>
> Implement QueryPerformanceCounter() and
> QueryPerformanceFrequency()
> for both Unix and Windows.
>
> This has been tested in both Unix and Windows in an
> application using
> TimerLib.
>
> Signed-off-by: Derek Lin <derek.l...@hpe.com>
> Signed-off-by: Kitty Chen <kitty.c...@hpe.com>
> ---
> EmulatorPkg/Unix/Host/EmuThunk.c | 40
> +++++++++++++++++++++-----------
> EmulatorPkg/Win/Host/WinThunk.c | 10 +++++---
> 2 files changed, 34 insertions(+), 16 deletions(-)
>
> diff --git a/EmulatorPkg/Unix/Host/EmuThunk.c
> b/EmulatorPkg/Unix/Host/EmuThunk.c
> index 1e9dc99187..92703d3088 100644
> --- a/EmulatorPkg/Unix/Host/EmuThunk.c
> +++ b/EmulatorPkg/Unix/Host/EmuThunk.c
> @@ -11,6 +11,7 @@
>
> Copyright (c) 2004 - 2019, Intel Corporation. All
> rights reserved.<BR>
> Portions copyright (c) 2008 - 2011, Apple Inc. All
> rights reserved.<BR>
> +(C) Copyright 2020 Hewlett Packard Enterprise
> Development LP<BR>
> SPDX-License-Identifier: BSD-2-Clause-Patent
>
> **/
> @@ -33,6 +34,7 @@ struct timeval settimer_timeval;
> UINTN settimer_callback = 0;
>
> BOOLEAN gEmulatorInterruptEnabled = FALSE;
> +UINT64 mPerformanceFrequency = 0;
>
>
> UINTN
> @@ -236,16 +238,6 @@ SecInterruptEanbled (void)
> return gEmulatorInterruptEnabled;
> }
>
> -
> -UINT64
> -QueryPerformanceFrequency (
> - VOID
> - )
> -{
> - // Hard code to nanoseconds
> - return 1000000000ULL;
> -}
> -
> UINT64
> QueryPerformanceCounter (
> VOID
> @@ -274,12 +266,34 @@ QueryPerformanceCounter (
>
> return (Start * sTimebaseInfo.numer) /
> sTimebaseInfo.denom;
> #else
> - // Need to figure out what to do for Linux?
> - return 0;
> + int status;
> + struct timespec time;
> + status = clock_gettime(CLOCK_REALTIME, &time);
> + return MultU64x32 (time.tv_sec, 1000000000) +
> time.tv_nsec;
> +
> #endif
> }
>
> -
> +UINT64
> +QueryPerformanceFrequency (
> + VOID
> + )
> +{
> + UINT64 Counter1;
> + UINT64 Counter2;
> + if (mPerformanceFrequency) {
> + return mPerformanceFrequency;
> + }
> + //
> + // Don't know how to query performance frequency in
> Linux,
> + // so instead, sleep 0.1 second and calculate it.
> + //
> + Counter1 = QueryPerformanceCounter();
> + SecSleep (100* 1000 * 1000);
> + Counter2 = QueryPerformanceCounter();
> + mPerformanceFrequency = (Counter2-Counter1) * 10;
> + return mPerformanceFrequency;
> +}
>
> VOID
> SecSleep (
> diff --git a/EmulatorPkg/Win/Host/WinThunk.c
> b/EmulatorPkg/Win/Host/WinThunk.c
> index a77be2a64b..41b5cffe18 100644
> --- a/EmulatorPkg/Win/Host/WinThunk.c
> +++ b/EmulatorPkg/Win/Host/WinThunk.c
> @@ -1,6 +1,7 @@
> /**@file
>
> Copyright (c) 2006 - 2018, Intel Corporation. All
> rights reserved.<BR>
> +(C) Copyright 2020 Hewlett Packard Enterprise
> Development LP<BR>
> SPDX-License-Identifier: BSD-2-Clause-Patent
>
> Module Name:
> @@ -438,8 +439,9 @@ SecQueryPerformanceFrequency (
> VOID
> )
> {
> - // Hard code to nanoseconds
> - return 1000000000ULL;
> + UINT64 Frequency;
> + QueryPerformanceFrequency ((LARGE_INTEGER *)
> &Frequency);
> + return Frequency;
> }
>
> UINT64
> @@ -447,7 +449,9 @@ SecQueryPerformanceCounter (
> VOID
> )
> {
> - return 0;
> + UINT64 PerformanceCount;
> + QueryPerformanceCounter ((LARGE_INTEGER *)
> &PerformanceCount);
> + return PerformanceCount;
> }
>
>
> --
> 2.17.0.windows.1
>
>
>
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