Scalegrid

APRIL 23, 2021

Both Redis and Memcached are: NoSQL in-memory data structures Written in C Open source Used to speed up applications Support sub-millisecond latency In 2014, Salvatore wrote an excellent StackOverflow post on […]. Memcached, on the other hand, was created in 2003 by Brad Fitzpatrick.

Open Source 264

Open Source Latency C++ Speed 264

Brendan Gregg

AUGUST 29, 2021

biolatency From [bcc], this eBPF tool shows a latency histogram of disk I/O. Hit Ctrl-C to end. ^C C msecs : count distribution 0 -> 1 : 83 | | 2 -> 3 : 20 | | 4 -> 7 : 0 | | 8 -> 15 : 41 | | 16 -> 31 : 1620 | * | 32 -> 63 : 8139 | *| 64 -> 127 : 176 | | 128 -> 255 : 95 | | 256 -> 511 : 61 | | 512 -> 1023 : 93 | |. 41 33681 ^C.

Cache 105

Cache C++ AWS Latency 105

Brendan Gregg

JULY 2, 2021

biolatency Disk I/O latency histogram heat map. runqlat CPU scheduler latency heat map. Then, having discovered everything is C or Python, some rewrite it all in a different language. For a more recent example, I wrote cachestat(8) while on vacation in 2014 for use on the Netflix cloud, which was a mix of Linux 3.2

Latency 145

Latency Cache Energy Systems 145

ACM Sigarch

MARCH 25, 2019

How many buffers are needed to track pending requests as a function of needed bandwidth and expected latency? Can one both minimize latency and maximize throughput for unscheduled work? The M/M/1 queue will show us a required trade-off among (a) allowing unscheduled task arrivals, (b) minimizing latency, and (c) maximizing throughput.

Systems 53

Systems Latency Performance C++ 53

ACM Sigarch

MARCH 18, 2019

How many buffers are needed to track pending requests as a function of needed bandwidth and expected latency? Can one both minimize latency and maximize throughput for unscheduled work? These models are useful for insight regarding the basic computer system performance metrics of latency and throughput (bandwidth). Little’s Law.

Systems 60

Systems Latency Performance Analytics 60

Brendan Gregg

AUGUST 29, 2021

100.00 ^C I'm looking at the r_await column in particular: the average wait time for reads in milliseconds. biolatency From [bcc], this eBPF tool shows a latency histogram of disk I/O. Hit Ctrl-C to end. ^C Hit Ctrl-C to end. ^C avg-cpu: %user %nice %system %iowait %steal %idle 14.81 I think it's the workload. ## 4.

Cache 40

Cache C++ AWS Systems 40

Brendan Gregg

JULY 2, 2021

biolatency Disk I/O latency histogram heat map 5. runqlat CPU scheduler latency heat map 10. As an extreme example, I wrote cachestat(8) while on vacation in 2014 for use on the Netflix cloud, which was a mix of Linux 3.2 Then, having discovered everything is C or Python, some rewrite it all in a different language.

Open Source 40

Open Source Latency Cache Energy 40