System and method for time stamp synchronization

Patent metadata

Field	Value
Publication number	US-10719100-B2
Application number	US-201816012236-A
Country	US
Kind code	B2
Filing date	Jun 19, 2018
Priority date	Nov 21, 2017
Publication date	Jul 21, 2020
Grant date	Jul 21, 2020

Abstract

A system and method for time stamp synchronization are disclosed. In one embodiment, first and second devices are provided. The second device receives a first time stamp of the first device, wherein the first time stamp was generated in response to a time stamp synchronization event common to the first and second devices; generates a second time stamp of the second device in response to the time stamp synchronization event, wherein the first and second time stamps are in different time domains; and correlates the first and second time stamps, wherein correlating the first and second time stamps provide a relationship between the time domains because the first and second time stamps were both generated with respect to the same time stamp synchronization event common to the first and second devices.

First claim

What is claimed is:

1. A host comprising:
at least one interface through which to communicate with a first computing device comprising a first clock operating in a first time domain and a second computing device comprising a second clock operating in a second time domain; and
a processor configured to:
store, in each of first and second log entries, a common time stamp generated by a third clock operating in a third time domain;
send the first log entry to the first computing device, wherein the first computing device is configured to store a first additional time stamp in the first log entry and send the first log entry to a database external to the first and second computing devices; and
send the second log entry to the second computing device, wherein the second computing device is configured to store a second additional time stamp in the second log entry and send the second log entry to the database external to the first and second computing devices;

wherein:
the first, second, and third clocks are synchronized by a time server, but wherein a skew among at least two of the first, second, and third clocks nevertheless exists; and
analysis of the first and second log entries by the host, first computing device, or second computing device provides an indication of the skew between the at least two of the first, second, and third clocks.

2. The host of claim 1 , further comprising a storage system; wherein one of the first and second log entries is a log from the storage system.

3. The host of claim 2 , wherein the storage system comprises a three-dimensional memory.

4. The host of claim 1 , wherein at least one of the log entries comprises a kernel (kmsg) log entry and a logcat log entry.

5. The host of claim 1 , wherein storing the common time stamp in each of the first and second log entries is performed as a simultaneous operation.

6. A method for stamp synchronization, the method comprising:
performing the following in a host, wherein the host is part of a system comprising a first device and a second device, wherein each of the host and first and second devices comprises a respective clock operating in a respective time domain:
providing a common time stamp to first and second log entries using a clock in the host; and
sending the first and second log entries from the host to the first and second devices, respectively, wherein the first and second devices provide their own time stamp to the log entries, whereby the first and second log entries have two time stamps: the common time stamp provided by the host and a time stamp provided by one of the devices and wherein the first and second devices are configured to send the first and second log entries to a database external to the first and second devices;

wherein:
the clocks of the host and first and second devices are synchronized by a time server, but wherein a skew among at least two of the clocks nevertheless exists; and
analysis of the first and second log entries by the host, first device, or second device provides an indication of the skew between the at least two of the clocks.

7. The method of claim 6 , wherein:
the host comprises a storage system; and
one of the first and second log entries is from a log in the storage system.

8. The method of claim 7 , wherein the storage system comprises a three-dimensional memory.

9. The method of claim 6 , wherein at least one of the log entries comprises a kernel (kmsg) log entry and a logcat log entry.

10. The method of claim 6 , wherein providing the common time stamp is a simultaneous operation.

11. A host comprising:
at least one interface through which to communicate with a first computing device comprising a first clock operating in a first time domain and a second computing device comprising a second clock operating in a second time domain;
means for storing, in each of first and second log entries, a common time stamp generated by a third clock operating in a third time domain;
means for sending the first log entry to the first computing device, wherein the first computing device is configured to store a first additional time stamp in the first log entry and send the first log entry to a database external to the first and second computing devices; and
means for sending the second log entry to the second computing device, wherein the second computing device is configured to store a second additional time stamp in the second log entry and send the second log entry to the database external to the first and second computing devices;
wherein:
the first, second, and third clocks are synchronized by a time server, but wherein a skew among at least two of the first, second, and third clocks nevertheless exists; and
analysis of the first and second log entries by the host, first computing device, or second computing device provides an indication of the skew between the at least two of the first, second, and third clocks.

12. The host of claim 11 , further comprising a storage system, and wherein one of the first and second log entries is a log from the storage system.

13. The host of claim 12 , wherein the storage system comprises a three dimensional memory.

14. The host of claim 11 , wherein at least one of the log entries comprises a kernel (kmsg) log and a logcat log.

15. The host of claim 11 , wherein storing the common time stamp is performed as a simultaneous operation.

Assignees

• Western Digital Tech Inc

Inventors

• Zaidman Mikhael
• Brief David C
• Levi Shai

Classifications

• G06F1/14 Primary

  Time supervision arrangements, e.g. real time clock · CPC title

• G06F1/12 Primary

  Synchronisation of different clock signals {provided by a plurality of clock generators} · CPC title

• H04L7/02

  Speed or phase control by the received code signals, the signals containing no special synchronisation information {(H04L7/0075 takes precedence)} · CPC title

• G06F2201/86

  Event-based monitoring · CPC title

• G06F11/3072

  where the reporting involves data filtering, e.g. pattern matching, time or event triggered, adaptive or policy-based reporting · CPC title