Nick Desaulniers

OCTOBER 24, 2018

Before booting a compiled Linux kernel image on actual hardware, it can save us time and potential headache to do a quick boot in a virtual machine like QEMU. s -S & $ gdb vmlinux ( gdb ) target remote :1234 ( gdb ) hbreak start_kernel ( gdb ) c ( gdb ) lx-dmesg. Try ctrl+a , then c , to get a (qemu) prompt.

C++ 56

C++ Hardware Virtualization Systems 56

Brendan Gregg

AUGUST 18, 2019

It was created by Alastair Robertson, a talented UK-based developer who has previously won various coding competitions. bpftrace uses BPF (Berkeley Packet Filter), an in-kernel execution engine that processes a virtual instruction set. hardware Hardware counter-based instrumentation. Attaching 2 probes. ^C bashreadline.bt

Latency 68

Latency C++ Cache Programming 68

Nick Desaulniers

MAY 30, 2016

Three C/C++ programmers walk into a bar. Simultaneously, they’re all right, but they’re also all wrong (and need a lesson about portable C code). This post is more about considerations when porting older code to newer machines, not about porting newer code to run on older machines. What the hell is going on?

C++ 59

C++ Programming Code Hardware 59

Adrian Cockcroft

JUNE 21, 2022

I became the Sun UK local specialist in performance and hardware, and as Sun transitioned from a desktop workstation company to sell high end multiprocessor servers I was helping customers find and fix scalability problems. We had specializations in hardware, operating systems, databases, graphics, etc. that a lot of people used.

Tuning 52

Tuning Benchmarking Engineering C++ 52

HammerDB

JUNE 27, 2022

It enables the user to measure database performance and make comparative judgements about database hardware and software. These factors meant that often when looking for database performance information, the results for a particular combination of software and hardware were not available. What is HammerDB? Why HammerDB was developed.

Benchmarking 62

Benchmarking Open Source C++ Cache 62

Brendan Gregg

SEPTEMBER 25, 2021

CLI tools The Cassandra systems were EC2 virtual machine (Xen) instances. The broken Java stacks turned out to be beneficial: They helped group together the os::javaTimeMillis() calls which otherwise might have have been scattered on top of different Java code paths, appearing as thin stacks everywhere. But I'm not completely sure.

Speed 126

Speed Java AWS Virtualization 126

Nick Desaulniers

APRIL 6, 2020

halt (); Some sort of very early exception handler; better to sit busy in an infinite loop than run off and destroy hardware or corrupt data, I suppose. Jann Horn gets back to me first: Can you use QEMU to look at the hardware frame (which contains values pushed by the hardware in response to the page fault) in early_idt_handler_common?

C++ 67

C++ Hardware Code Virtualization 67

KeyCDN

FEBRUARY 22, 2023

Chatbots and virtual assistants Chatbots and virtual assistants are becoming more common on websites and web applications as they provide an efficient and convenient way for users to interact with a business. Developers can easily share and access code and other resources regardless of their location.

Artificial Intelligence 111

Artificial Intelligence Development Serverless Website 111

HammerDB

FEBRUARY 25, 2021

To benchmark a database we introduce the concept of a Virtual User. For HammerDB both TPROC-C and TPROC-H run all of their workloads on the database being tested in SQL. The following is an example from TPROC-C from SQL Server. TPROC-C however is derived from the TPC-C specification and requires application logic around the SQL.

Programming 67

Programming Benchmarking Virtualization C++ 67

Testsigma

FEBRUARY 3, 2021

Mobiles have different models, screen resolutions, operating systems, network types, hardware configurations, etc. Also, how to test the hardware of the mobile phone itself, is it supporting all the software as it should? Let us have a look at the most popular types of mobile testing for applications and hardware.

Mobile 82

Mobile Testing Hardware C++ 82

Brendan Gregg

SEPTEMBER 25, 2021

CLI tools The Cassandra systems were EC2 virtual machine (Xen) instances. The broken Java stacks turned out to be beneficial: They helped group together the os::javaTimeMillis() calls which otherwise might have have been scattered on top of different Java code paths, appearing as thin stacks everywhere. But I'm not completely sure.

Speed 52

Speed Java AWS Virtualization 52

SQL Server According to Bob

DECEMBER 18, 2018

Before all was said and done, all of these people and more helped with various activities: · Eugene, Mike, Slava, Scott, Peter, Steve and others doing code reviews on my SQL Server and Host Extension changes. · Red Hat, SUSE, HPE, Intel helping and confirming Linux behaviors and making file system code changes. product: Virtual Disk.

Servers 90

Servers Media Cache Storage 90

Brendan Gregg

SEPTEMBER 25, 2021

CLI tools The Cassandra systems were EC2 virtual machine (Xen) instances. The broken Java stacks turned out to be beneficial: They helped group together the os::javaTimeMillis() calls which otherwise might have have been scattered on top of different Java code paths, appearing as thin stacks everywhere. But I'm not completely sure.

Speed 40

Speed Java AWS Virtualization 40

The Morning Paper

DECEMBER 8, 2019

Byte-addressable non-volatile memory,) NVM will fundamentally change the way hardware interacts, the way operating systems are designed, and the way applications operate on data. Traditional pointers address a memory location (often virtual of course). At least, the nature of pointers that we want to make persistent.

Hardware 56

Hardware Programming Media Storage 56

HammerDB

OCTOBER 12, 2018

This post complements the previous best practice guides this time with the focus on MySQL and MariaDB and achieving top levels of performance with the HammerDB MySQL TPC-C test. As is also the case this limitation is at the database level (especially the storage engine) rather than the hardware level. order by c.

Best Practices 40

Best Practices Scalability Performance C++ 40

Brendan Gregg

SEPTEMBER 5, 2017

It uses a Solaris Porting Layer (SPL) to provide a Solaris-kernel interface on Linux, so that unmodified ZFS code can execute. There's also a ZFS send/recv code path that should try to use the TASK_INTERRUPTIBLE flag (as suggested by a coworker), to avoid a kernel hang (can't kill -9 the process). Hit Ctrl-C to end. ^C

Virtualization 76

Virtualization AWS Engineering Hardware 76

The Morning Paper

APRIL 2, 2019

Root of trust (RoT) establishment on an untrusted system ensures that a system state comprises all and only content chosen by the user, and the user’s code begins execution in that state. In this context it means there are no external dependencies on e.g. secrets, trusted hardware modules, or special instructions (e.g. Implementation.

Software 40

Software Software Programming Hardware 40

Brendan Gregg

AUGUST 8, 2017

Nowadays, the source code to old operating systems can also be found online. TABLE OF EXP(-T/C) FOR T = 5 SEC. EXPFF: EXP 0.920043902 ;C = 1 MIN EXP 0.983471344 ;C = 5 MIN EXP 0.994459811 ;C = 15 MIN. Linux is also hard coding the 1, 5, and 15 minute constants. This, too, was a dead end.

Latency 111

Latency Metrics C++ Systems 111

SQL Server According to Bob

JANUARY 11, 2020

Character POS ASCII Value Formula Value A 1 65 67 C 2 67 69 Checksum 136 Comparing ​​ the checksum values indicates ​​ that the values do not match and ​​ damage ​​ has occurred to the data. ​​ Remote mirroring captures writes and duplicates them ​​ remotely.

Servers 40

Servers Cache Database Media 40

Smashing Magazine

JANUARY 11, 2021

Have we optimized enough with tree-shaking, scope hoisting, code-splitting, and all the fancy loading patterns with intersection observer, progressive hydration, clients hints, HTTP/3, service workers and — oh my — edge workers? It’s much easier to reach performance goals when the code base is fresh or is just being refactored.

Performance 145

Performance Cache Media Metrics 145