What exactly is NVMe? What are the advantages of using its SSD?
2015-8-20 14:00| Author: Strike| Keywords: NVMe, SSD, PCI-E SSD, Super Class
Friends who are concerned about SSD should hear the word NVMe more frequently this year. With high-end SSD The battlefield has abandoned SATA and moved to PCI-E. The old AHCI standard is out of fashion. The future belongs to NVMe. So what exactly is NVMe?
Play Friends who have used SSD should all know that if you want to make SSD play a real strength, you need to switch the SATA controller mode to AHCI in the BIOS. For SATA devices, using AHCI mode is indeed the right choice. Switching to AHCI can get better Performance. But now the latest storage interface M.2 and SATA-E interface are both PCI-E channels. For PCI-E, AHCI is not a good choice. In order to achieve the best performance, a new standard-NVMe is required. .
Intel 750 is the representative of NVMe SSD
Friends who are concerned about SSD should hear the word NVMe this year. Driven by Samsung, it has now entered the consumer market. As the battlefield of high-end SSDs has shifted to PCI-E and M.2 interfaces, the old AHCI standard has become outdated, and more and more master control manufacturers have launched NVMe-supporting For master control, more SSDs supporting the NVMe standard will be introduced to the market in the future, so what exactly is NVMe?
If you say You should know more about AHCI. NVMe is actually the same as AHCI as a logical device interface standard (It is an interface standard, not an interface! Not an interface! Not an interface! Because it is important, I say three times), NVMe The full name is Non-Volatile Memory Express, a non-volatile memory standard. It is a specification for SSDs that use PCI-E channels. The low latency and parallelism of PCI-E SSDs were fully utilized at the beginning of the design of NVMe. The parallelism of contemporary processors, platforms and applications. The parallelism of SSDs can be fully utilized by the hardware and software of the host. Compared with the current AHCI standard, the NVMe standard can bring many performance improvements.
The origin of NVMe
The current SATA interface and AHCI standard are actually designed for high-latency mechanical hard drives, and mainstream SSDs still continue to use them. , When the performance of early SSD is not high, you may not feel that there is any problem, but as the performance of SSD gradually increases, these standards have become a major bottleneck restricting SSDs. The AHCI standard designed for mechanical hard drives is not suitable for low latency. When the SSD.
Of course, the industry has long been aware of this problem. In the second half of 2009, the technical work on NVMe was officially launched. The NVMe specification was customized by a working group including more than 90 companies. Intel is the main The leader, the team members include companies such as Micron, Dell, Samsung, Marvell, NetAPP, EMC, IDT, etc. The purpose is to establish a new storage specification standard for SSD and free it from the old SATA and AHCI.
In 2011, the NVMe standard was officially released. The standard was tailored to the characteristics of flash storage. The new standard lifted the various restrictions imposed by the old standard on SSDs. The standard was upgraded to NVMe 1.1 in 2012, and the latest NVMe 1.2 standard was launched in 2014.
The first product supporting the NVMe standard was Samsung XS1715, which was released in July 2013, followed by the launch of enterprise-level NVMe standard SSDs. It was not until Intel 750 was released this year that NVMe standard products began to enter Consumer market.
NVMe advantage one: low latency
When it comes to the advantages of the NVMe standard compared to the AHCI standard, one of them is the low latency. The above picture is more intuitive. The NVMe standard is for PCI- For E SSD, using the native PCI-E channel to directly connect to the CPU can avoid the delay caused by the communication between the external controller (PCH) of the SATA and SAS interface and the CPU.
In terms of software layer, the delay of NVMe standard is less than half that of AHCI. NVMe streamlines the calling method and does not need to read registers when executing commands; while each command of AHCI needs to be read 4 times Registers, a total of 8000 CPU cycles will be consumed, resulting in a delay of about 2.5 microseconds.
Lower delay can be Let SSD’s 4KB QD1 transmission capacity skyrocket
NVMe advantage two: IOPS greatly increase
In addition, NVMe has also greatly improved the IOPS performance of SSDs. The idea of parallelism when formulating the AHCI specification It is not fully integrated into the specification, and the transmission capacity can be optimized by using the NCQ function, but the interface does not allow the SSD to truly maximize its due parallelism.
Currently, SSD tests usually only test the IOPS capability with a queue depth of 32 at most. In fact, this is the upper limit of AHCI after all. In fact, many flash memory masters can provide better queue depth. NVMe can increase the maximum queue depth from 32 to 64,000, and the IOPS capability of SSDs will also be greatly improved.
NVMe also It supports receiving commands and prioritizing requests from multi-core processors at the same time. This feature will show its advantages under heavy load at the enterprise level.
The advantage of low latency and good parallelism is that the random performance of the SSD can be greatly improved. The Intel 750 we tested is an NVMe SSD, and its random performance is absolutely top-notch , It can play an excellent speed at any queue depth.
NVMe advantage three: lower power consumption
NVMe has added automatic power state switching and dynamic power management functions. The device can be switched to Power State 1 after being idle for 50ms from Power State 0 If it continues to be idle, it will enter Power State 2 with lower power consumption after 500ms, and there will be a short delay when switching. When the SSD is idle, it can be controlled very quickly at a very low level. In terms of power consumption management, the NVMe standard SSD will have a greater advantage than the current mainstream AHCI SSD. This is especially important for mobile devices, which can significantly increase the number of notebooks. And the endurance of the tablet.
NVMe advantage four: wide driver applicability
The compatibility of drivers is also a common problem of all PCI-E SSDs. Each product has dedicated drivers for different systems. On the one hand, some manufacturers are doing very well, while others are not so good. However, many PCI-E SSDs need to be loaded with drivers to be able to boot normally.
The emergence of the NVMe standard solves this problem. NVMe SSD can easily match different platforms and systems. It can work normally without the corresponding driver provided by the manufacturer. At present, Windows, Linux, Solaris, Unix, VMware , UEFI, etc. have added support for NVMe SSD. Of course, Intel products have their own drivers. If you don’t install the Intel drivers, the SSD can work normally, but the performance cannot be fully utilized. This problem occurred when I tested the Intel 750 before. Other manufacturers don’t know how.
What exactly is NVMe? What are the advantages of using its SSD?
2015-8-20 14:00| Author: Strike| Keywords: NVMe, SSD, PCI-E SSD, Super Class
Share to
Friends who are concerned about SSD should hear the word NVMe more frequently this year. With high-end SSD The battlefield has abandoned SATA and moved to PCI-E. The old AHCI standard is out of fashion. The future belongs to NVMe. So what exactly is NVMe?
This article is about 1,777 words, it takes 3 minutes to read
Friends who have played SSD should all know that if you want to make SSD play its true strength, you must go In the BIOS, the SATA controller mode is switched to AHCI. It is indeed the right choice for SATA devices to use AHCI mode. Switching to AHCI can achieve better performance. But now the latest storage interface M.2 and SATA-E interface are both PCI-E channels. For PCI-E, AHCI is not a good choice. In order to achieve the best performance, a new standard-NVMe is required. .
Intel 750 is the representative of NVMe SSD
Friends who are concerned about SSD should hear the word NVMe this year. Driven by Samsung, it has now entered the consumer market. As the battlefield of high-end SSDs has shifted to PCI-E and M.2 interfaces, the old AHCI standard has become outdated, and more and more master control manufacturers have launched NVMe-supporting For master control, more SSDs supporting the NVMe standard will be introduced to the market in the future, so what exactly is NVMe?
If you say You should know more about AHCI. NVMe is actually the same as AHCI as a logical device interface standard (It is an interface standard, not an interface! Not an interface! Not an interface! Because it is important, I say three times), NVMe The full name is Non-Volatile Memory Express, a non-volatile memory standard. It is a specification for SSDs that use PCI-E channels. The low latency and parallelism of PCI-E SSDs were fully utilized at the beginning of the design of NVMe. The parallelism of contemporary processors, platforms and applications. The parallelism of SSDs can be fully utilized by the hardware and software of the host. Compared with the current AHCI standard, the NVMe standard can bring many performance improvements.
The origin of NVMe
The current SATA interface and AHCI standard are actually designed for high-latency mechanical hard drives, and mainstream SSDs still continue to use them. , When the performance of early SSD is not high, you may not feel that there is any problem, but as the performance of SSD gradually increases, these standards have become a major bottleneck restricting SSDs. The AHCI standard designed for mechanical hard drives is not suitable for low latency. When the SSD.
Of course, the industry has long been aware of this problem. In the second half of 2009, the technical work on NVMe was officially launched. The NVMe specification was customized by a working group including more than 90 companies. Intel is the main The leader, the team members include companies such as Micron, Dell, Samsung, Marvell, NetAPP, EMC, IDT, etc. The purpose is to establish a new storage specification standard for SSD and free it from the old SATA and AHCI.
In 2011, the NVMe standard was officially released. The standard was tailored to the characteristics of flash storage. The new standard lifted the various restrictions imposed by the old standard on SSDs. The standard was upgraded to NVMe 1.1 in 2012, and the latest NVMe 1.2 standard was launched in 2014.
The first product supporting the NVMe standard was Samsung XS1715, which was released in July 2013, followed by the launch of enterprise-level NVMe standard SSDs. It was not until Intel 750 was released this year that NVMe standard products began to enter Consumer market.
NVMe advantage one: low latency
When it comes to the advantages of the NVMe standard compared to the AHCI standard, one of them is the low latency. The picture above is more intuitive. The NVMe standard is PCI-oriented. For E SSD, using the native PCI-E channel to directly connect to the CPU can avoid the delay caused by the communication between the external controller (PCH) of the SATA and SAS interface and the CPU.
In terms of software layer, the delay of NVMe standard is less than half that of AHCI. NVMe streamlines the calling method and does not need to read registers when executing commands; while each command of AHCI needs to be read 4 times Registers, a total of 8000 CPU cycles will be consumed, resulting in a delay of about 2.5 microseconds.
Lower delay can be Let SSD’s 4KB QD1 transmission capacity skyrocket
NVMe advantage two: IOPS greatly increase
In addition, NVMe has also greatly improved the IOPS performance of SSDs. The idea of parallelism when formulating the AHCI specification It is not fully integrated into the specification, and the transmission capacity can be optimized by using the NCQ function, but the interface does not allow the SSD to truly maximize its due parallelism.
Currently, SSD tests usually only test the IOPS capability with a queue depth of 32 at most. In fact, this is the upper limit of AHCI after all. In fact, many flash memory masters can provide better queue depth. NVMe can increase the maximum queue depth from 32 to 64,000, and the IOPS capability of SSDs will also be greatly improved.
NVMe also It supports receiving commands and prioritizing requests from multi-core processors at the same time. This feature will show its advantages under heavy load at the enterprise level.
The advantage of low latency and good parallelism is that the random performance of the SSD can be greatly improved. The Intel 750 we tested is an NVMe SSD, and its random performance is absolutely top-notch , It can play an excellent speed at any queue depth.
NVMe advantage three: lower power consumption
NVMe has added automatic power state switching and dynamic power management functions. The device can be switched to Power State 1 after being idle for 50ms from Power State 0 If it continues to be idle, it will enter Power State 2 with lower power consumption after 500ms, and there will be a short delay when switching. When the SSD is idle, it can be controlled very quickly at a very low level. In terms of power consumption management, the NVMe standard SSD will have a greater advantage than the current mainstream AHCI SSD. This is especially important for mobile devices, which can significantly increase the number of notebooks. And the endurance of the tablet.
NVMe advantage four: wide driver applicability
The compatibility of drivers is also a common problem of all PCI-E SSDs. Each product has dedicated drivers for different systems. On the one hand, some manufacturers are doing very well, while others are not so good. However, many PCI-E SSDs need to be loaded with drivers to be able to boot normally.
The emergence of the NVMe standard solves this problem. NVMe SSD can easily match different platforms and systems. It can work normally without the corresponding driver provided by the manufacturer. At present, Windows, Linux, Solaris, Unix, VMware , UEFI, etc. have added support for NVMe SSD. Of course, Intel’s products have their own drivers. If the Intel driver is not installed, the SSD can work normally, but the performance cannot be fully utilized. There was this problem when testing the Intel 750 before, and other manufacturers don’t know how.