SHAPING I/O TRAFFIC BY MANAGING QUEUE DEPTH IN FRACTIONAL INCREMENTS

• US 20160210059A1
• Filed: 03/28/2016
• Published: 07/21/2016
• Est. Priority Date: 06/20/2014
• Status: Active Grant

• Current Assignee: Dell International LLC (Dell Technologies Inc.)
• Original Assignee: Dell International LLC (Dell Technologies Inc.)
• Inventors: Oelke, Dan
• Granted Patent: US 9,575,667 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 11/1446 Point-in-time backing up or restoration of persistent data
• CPC Class Codes: G06F 11/3034 where the computing system component is a storage system, e.g. DASD based or network based digital input from or digital output to record carriers G06F3/06; digital recording or reproducing G11B20/18; for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS], H04L67/1097
• CPC Class Codes: G06F 11/3048 where the topology of the computing system or computing system component explicitly influences the monitoring activity, e.g. serial, hierarchical systems
• CPC Class Codes: G06F 11/3419 by assessing time
• CPC Class Codes: G06F 11/3433 for load management allocation of a server based on load conditions G06F9/505; load rebalancing G06F9/5083; redistributing the load in a network by a load balancer H04L67/1029
• CPC Class Codes: G06F 11/3452 Performance evaluation by statistical analysis
• CPC Class Codes: G06F 11/3485 for I/O devices
• CPC Class Codes: G06F 12/145 the protection being virtual, e.g. for virtual blocks or segments before a translation mechanism
• CPC Class Codes: G06F 13/161 with latency improvement
• CPC Class Codes: G06F 13/1642 with request queuing
• CPC Class Codes: G06F 2201/875 Monitoring of systems including the internet
• CPC Class Codes: G06F 3/0611 in relation to response time
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/0665 at area level, e.g. provisioning of virtual or logical volumes
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD
• CPC Class Codes: H04L 43/0888 Throughput
• CPC Class Codes: H04L 63/0807 using tickets, e.g. Kerberos cryptographic mechanisms or cryptographic arrangements for entity authentication using tickets or tokens H04L9/3213

Abstract

A method for managing input/output (I/O) traffic in an information handling system. The method may include receiving electronic I/O requests from a network-attached server, determining a queue depth limit, monitoring latency of processed electronic I/O requests, and processing received electronic I/O requests. The number of electronic I/O requests permitted to be processed over a period of time may be based on a mathematical combination of the queue depth limit and a latency of processed electronic I/O requests. The determined queue depth limit may be a fractional value.

Claims

1. A method for managing input/output (I/O) traffic in an information handling system, the method comprising:

receiving electronic I/O requests from a network-attached server;

determining a queue depth limit;

monitoring latency of processed electronic I/O requests; and

processing received electronic I/O requests, wherein the number of electronic I/O requests permitted to be processed over a period of time is based on a mathematical combination of the queue depth limit and a latency of processed electronic I/O requests.

2. The method of claim 1, wherein processing received I/O requests comprises:

managing a virtual bucket comprising a number of virtual tokens, each token representative of authorization for an I/O request to be processed; and

permitting a received I/O request to be processed if the virtual bucket comprises a number of virtual tokens greater than zero, and decrementing the number of virtual tokens by at least one.

3. The method of claim 2, wherein the virtual tokens are added to the virtual bucket at any given time t_x according to the equation:

Tokens(t_x)=QueueDepthLimit*TimeElapsed(t_x−

t_x-1)/Latency

wherein Tokens(t_x) gives a value corresponding to a number of virtual tokens to be added to the virtual bucket at time t_x;

QueueDepthLimit is the determined queue depth limit;

TimeElapsed(t_x−

t_x-1) is an amount of time elapsed between time t_x and a time t_x-1, where t_x-1 is a point in time prior to time t_x; and

Latency is a latency of processed electronic I/O requests that have completed during the time elapsed between time t_x and a time t_x-1.

4. The method of claim 3, wherein Tokens(t_x) is calculated at periodic intervals.

5. The method of claim 3, wherein Tokens(t_x) is calculated at random intervals.

6. The method of claim 3, wherein Tokens(t_x) is calculated when an I/O request is received.

7. The method of claim 4, wherein Tokens(t_x) is additionally calculated when an I/O request is received.

8. The method of claim 3, wherein the QueueDepthLimit is a fractional value.

9. The method of claim 1, wherein the queue depth limit is a fractional value.

10. The method of claim 2, wherein processing received I/O requests further comprises waiting to process a received I/O request if the virtual bucket comprises a number of virtual tokens less than zero until the virtual bucket receives additional virtual tokens.

18. The method of claim 1, wherein the queue depth limit for at least one of the network-attached servers is a fractional value.

11. A method for managing input/output (I/O) traffic in an information handling system, the method comprising:

receiving electronic I/O requests from a plurality of network-attached servers;

determining a queue depth limit for each of the plurality of network-attached servers;

monitoring latency of processed electronic I/O requests; and

processing received electronic I/O requests for each of the network-attached servers, wherein the number of electronic I/O requests permitted to be processed for a given network-attached server over a period of time is based on a mathematical combination of the queue depth limit determined for that network-attached server and a latency of processed electronic I/O requests.

12. The method of claim 11, wherein the queue depth limit for one of the plurality of network-attached servers is different than at least one other of the plurality of network-attached servers.

13. The method of claim 12, wherein processing received I/O requests for each of the network-attached servers comprises, for each of the network-attached servers:

managing a virtual bucket comprising a number of virtual tokens, each token representative of authorization for an I/O request from at least that network-attached server to be processed; and

permitting a received I/O request from that network-attached server to be processed if the virtual bucket comprises a number of virtual tokens greater than zero, and decrementing the number of virtual tokens by at least one.

14. The method of claim 13, wherein the virtual tokens are added to the virtual bucket at any given time t_x according to the equation:

Tokens(t_x)=QueueDepthLimit*TimeElapsed(t_x−

t_x-1)/Latency

wherein Tokens(t_x) gives a value corresponding to a number of virtual tokens to be added to the virtual bucket at time t_x;

QueueDepthLimit is the determined queue depth limit for that network-attached server;

TimeElapsed(t_x−

t_x-1) is an amount of time elapsed between time t_x and a time t_x-1, where t_x-1 is a point in time prior to time t_x; and

Latency is a latency of processed electronic I/O requests that have completed during the time elapsed between time t_x and a time t_x-1.

15. The method of claim 13, wherein Tokens(t_x) is calculated for each network-attached server when an I/O request is received from that network-attached server.

16. The method of claim 13, wherein Tokens(t_x) is calculated for each network-attached server at periodic intervals.

17. The method of claim 13, wherein the QueueDepthLimit for at least one of the network-attached servers is a fractional value.

19. An information handling system comprising:

a data storage system receiving I/O requests from two or more network-attached servers; and

a controller managing the data storage system and configured to;

store a queue depth limit for each of the plurality of network-attached servers;

monitor latency of processed I/O requests; and

process received I/O requests for each of the network-attached servers, wherein the number of I/O requests permitted to be processed for a given network-attached server over a period of time is based on a mathematical combination of the queue depth limit determined for that network-attached server and a latency of processed I/O requests.

20. The information handling system of claim 19, wherein the queue depth limit for at least one of the plurality of network-attached servers is a fractional value.