LOGGING EVENTS WITH TIMESTAMPS

摘要

A logging unit is used to log entries for events in a computer system. Each entry includes an n-bit timestamp field and a payload. The payload includes information about the event and the timestamp field includes the n least significant bits of an N-bit timestamp for the event, where N>n. If the n least significant bits of the timestamp have wrapped compared to the corresponding n bits of the timestamp of the preceding entry then a timing entry is logged which includes other bits of the timestamp. Therefore, an N-bit timestamp can be determined for an event, but only the n least significant bits of the timestamp are stored in the timestamp field of an entry for the event. Therefore, the time flow of events in the store is better maintained (by having a larger timestamp) without increasing the number of bits (n) in the timestamp field of each entry.

主权项

1. A logging unit that logs events by causing entries to be stored in a store, wherein each of said entries comprises an n-bit timestamp field and a payload, the logging unit comprising:
control logic configured to
determine from a clock a timestamp for an event which is to be logged, wherein the determined timestamp comprises N bits, where N>n;cause a timing entry which includes a set of k bits of the determined timestamp to be stored in the store if one or more of the N−n most significant bits of the determined timestamp are different to a corresponding one or more of the N−n most significant bits of a timestamp for a preceding event for which a preceding entry is stored in the store, said k bits being more significant bits of the determined timestamp than the n least significant bits of the determined timestamp; andcause an entry for the event to be stored in the store, wherein the n least significant bits of the determined timestamp are included in the timestamp field of the entry for the event.