Alberto García

O Grove (Spain)

One of the founding members of Igalia, Alberto loves computing since he got his first ZX Spectrum in the early nineties.

Latest Updates

Alberto García 08/02/2017

QEMU and the qcow2 metadata checks

When choosing a disk image format for your virtual machine one of the factors to take into considerations is its I/O performance. In this post I’ll talk a bit about the internals of qcow2 and about one of the aspects that can affect its performance...

Alberto García 24/05/2016

I/O bursts with QEMU 2.6

QEMU 2.6 was released a few days ago. One new feature that I have been working on is the new way to configure I/O limits in disk drives to allow bursts and increase the responsiveness of the virtual machine. In this post I’ll try to explain how it...

Alberto García 17/12/2015

Improving disk I/O performance in QEMU 2.5 with the qcow2 L2 cache

QEMU 2.5 has just been released, with a lot of new features. As with the previous release, we have also created a video changelog. I plan to write a few blog posts explaining some of the things I have been working on. In this one I’m going to talk...

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throttle: Remove throttle_fix_bucket() / throttle_unfix_bucket()

throttle: Remove throttle_fix_bucket() / throttle_unfix_bucket() The throttling code can change internally the value of bkt->max if it hasn't been set by the user. The problem with this is that if we want to retrieve the original value we have to...

Alberto García31/08/2017

throttle: Make throttle_is_valid() a bit less verbose

throttle: Make throttle_is_valid() a bit less verbose Use a pointer to the bucket instead of repeating cfg->buckets[i] all the time. This makes the code more concise and will help us expand the checks later and save a few line breaks. Signed-off-by:...

Alberto García31/08/2017

throttle: Update the throttle_fix_bucket() documentation

throttle: Update the throttle_fix_bucket() documentation The way the throttling algorithm works is that requests start being throttled once the bucket level exceeds the burst limit. When we get there the bucket leaks at the level set by the user...

Alberto García31/08/2017

throttle: Fix wrong variable name in the header documentation

throttle: Fix wrong variable name in the header documentation The level of the burst bucket is stored in bkt.burst_level, not bkt.burst_length. Signed-off-by: Alberto Garcia Reviewed-by: Manos Pitsidianakis Message-id:...

Alberto García31/08/2017

quorum: Set sectors-count to 0 when reporting a flush error

quorum: Set sectors-count to 0 when reporting a flush error The QUORUM_REPORT_BAD event has fields to report the sector in which the error was detected and the number of affected sectors starting from that one. This is important for read and write...

Alberto García08/08/2017