By: David Hess (davidwhess.delete@this.gmail.com), August 3, 2022 3:48 am
Room: Moderated Discussions
Doug S (foo.delete@this.bar.bar) on August 1, 2022 8:37 am wrote:
> anon2 (anon.delete@this.anon.com) on July 31, 2022 10:55 pm wrote:
> > The hard problem for NAND is random read latency.
>
> Can you expand on that further? What makes random reads a problem for NAND? True they
> aren't as fast as sequential but hardly seem to be an issue for modern SSDs.
The problem is that every random read requires loading an entire block, or perhaps a large fraction of a block, of 2048+64 or 4096+128 bytes and executing ECC before the data becomes available. That makes for a latency on the order of 50 microseconds or longer.
> anon2 (anon.delete@this.anon.com) on July 31, 2022 10:55 pm wrote:
> > The hard problem for NAND is random read latency.
>
> Can you expand on that further? What makes random reads a problem for NAND? True they
> aren't as fast as sequential but hardly seem to be an issue for modern SSDs.
The problem is that every random read requires loading an entire block, or perhaps a large fraction of a block, of 2048+64 or 4096+128 bytes and executing ECC before the data becomes available. That makes for a latency on the order of 50 microseconds or longer.
Topic | Posted By | Date |
---|---|---|
RIP Optane/XPoint | Wes Felter | 2022/07/28 07:53 PM |
RIP Optane/XPoint | Rayla | 2022/07/28 08:28 PM |
RIP Optane/XPoint | Doug S | 2022/07/28 09:00 PM |
RIP Optane/XPoint | NoSpammer | 2022/07/29 01:50 AM |
NVDIMM-N | Eric L | 2022/07/29 03:36 AM |
RIP Optane/XPoint | Michael S | 2022/07/29 04:02 AM |
RIP Optane/XPoint | Doug S | 2022/07/29 10:40 AM |
RIP Optane/XPoint | Doug S | 2022/07/29 10:43 AM |
RIP Optane/XPoint | Linus Torvalds | 2022/07/29 11:20 AM |
RIP Optane/XPoint | David Hess | 2022/07/29 08:59 PM |
RIP Optane/XPoint | David Hess | 2022/07/30 03:44 PM |
RIP Optane/XPoint | Doug S | 2022/07/30 10:43 PM |
RIP Optane/XPoint | rwessel | 2022/07/31 05:33 AM |
RIP Optane/XPoint | Konrad Schwarz | 2022/08/02 08:06 AM |
RIP Optane/XPoint | David Hess | 2022/08/02 10:24 PM |
RIP Optane/XPoint | David Hess | 2022/08/02 10:26 PM |
RIP Optane/XPoint | Adrian | 2022/08/03 01:19 AM |
RIP Optane/XPoint | anonymou5 | 2022/07/29 12:50 PM |
RIP Optane/XPoint | Gionatan Danti | 2022/07/29 09:09 AM |
RIP Optane/XPoint | Mark Roulo | 2022/07/29 10:02 AM |
RIP Optane/XPoint | dmcq | 2022/07/30 03:42 AM |
RIP Optane/XPoint | anon3 | 2022/07/31 10:19 PM |
RIP Optane/XPoint | anon2 | 2022/07/31 10:55 PM |
RIP Optane/XPoint | Doug S | 2022/08/01 08:37 AM |
RIP Optane/XPoint | Gionatan Danti | 2022/08/01 01:33 PM |
RIP Optane/XPoint | NoSpammer | 2022/08/02 03:50 AM |
RIP Optane/XPoint | Doug S | 2022/08/02 09:24 AM |
RIP Optane/XPoint | Gionatan Danti | 2022/08/02 10:34 AM |
RIP Optane/XPoint | --- | 2022/08/02 10:39 AM |
RIP Optane/XPoint | David Hess | 2022/08/03 03:48 AM |
RIP Optane/XPoint | Michael S | 2022/08/03 06:04 AM |
RIP Optane/XPoint | David Hess | 2022/08/03 08:56 AM |
RIP Optane/XPoint | Adrian | 2022/08/01 02:15 AM |
RIP Optane/XPoint | Gionatan Danti | 2022/08/01 06:07 AM |
Losses vs not profitable enough | Mark Roulo | 2022/08/01 10:15 AM |
Losses vs not profitable enough | dmcq | 2022/08/01 11:50 AM |
Losses vs not profitable enough | Gionatan Danti | 2022/08/01 12:34 PM |
RIP Optane/XPoint | Michael S | 2022/08/01 02:47 PM |
RIP Optane/XPoint | Anon | 2022/08/01 03:09 PM |
RIP Optane/XPoint | Michael S | 2022/08/01 03:32 PM |
RIP Optane/XPoint | Groo | 2022/08/01 12:28 PM |
RIP Optane/XPoint | anon3 | 2022/08/01 10:33 PM |
RIP Optane/XPoint | Groo | 2022/08/03 11:15 AM |
RIP Optane/XPoint | --- | 2022/08/03 03:05 PM |
Latency | David Kanter | 2022/07/29 06:35 PM |
Operating system and driver overhead | Eric L | 2022/07/29 03:44 AM |
Operating system and driver overhead | Linus Torvalds | 2022/07/29 10:45 AM |
altrernatives? | Michael S | 2022/07/29 05:17 AM |
altrernatives? | Rayla | 2022/07/29 06:49 AM |