From: "Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com>
To: rostedt@goodmis.org
Cc: linux-trace-devel@vger.kernel.org
Subject: [PATCH 0/3] trace-cmd: Align guest TSC calculation with the kernel
Date: Thu, 23 Sep 2021 12:45:23 +0300 [thread overview]
Message-ID: <20210923094526.765059-1-tz.stoyanov@gmail.com> (raw)
The formula for calculating guest TSC clock, used in the kernel is:
guest_tsc = tsc-offset + (host_tsc * tsc-scaling-ratio) >> tsc-scaling-ratio-frac-bits
Current trace-cmd implementation does not take into account fraction
bits, when calculating guest clock offset in case of a clock scaling.
Additional logic is added, to use the same formula in trace-cmd. The changes
are backward compatible with trace-cmd 2.9.
The changes are not tested with a kernel that has guest clock scaling enabled.
The goal of the patch set is to extend the time sync option, saved in the
guest trace.dat file, with all needed data used in the kernel for guest TSC
calculations.
Tzvetomir Stoyanov (VMware) (3):
trace-cmd: Extend host-guest time sync with fraction bits
trace-cmd: Read and use fraction bits from TRACECMD_OPTION_TIME_SHIFT
trace-cmd: Dump fraction bits from TRACECMD_OPTION_TIME_SHIFT
.../include/private/trace-cmd-private.h | 4 +-
lib/trace-cmd/include/trace-tsync-local.h | 7 +-
lib/trace-cmd/trace-input.c | 79 +++++++-------
lib/trace-cmd/trace-timesync-kvm.c | 59 +++++++---
lib/trace-cmd/trace-timesync-ptp.c | 4 +-
lib/trace-cmd/trace-timesync.c | 49 +++++++--
tracecmd/trace-dump.c | 102 +++++++++++++-----
7 files changed, 205 insertions(+), 99 deletions(-)
--
2.31.1
next reply other threads:[~2021-09-23 9:45 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-23 9:45 Tzvetomir Stoyanov (VMware) [this message]
2021-09-23 9:45 ` [PATCH 1/3] trace-cmd: Extend host-guest time sync with fraction bits Tzvetomir Stoyanov (VMware)
2021-10-13 3:04 ` Steven Rostedt
2021-10-13 9:48 ` Tzvetomir Stoyanov
2021-10-13 14:53 ` Steven Rostedt
2021-09-23 9:45 ` [PATCH 2/3] trace-cmd: Read and use fraction bits from TRACECMD_OPTION_TIME_SHIFT Tzvetomir Stoyanov (VMware)
2021-10-13 3:14 ` Steven Rostedt
2021-10-13 10:03 ` Tzvetomir Stoyanov
2021-09-23 9:45 ` [PATCH 3/3] trace-cmd: Dump " Tzvetomir Stoyanov (VMware)
2021-10-13 3:15 ` Steven Rostedt
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