CachingWhen running beats downloading
When running beats downloading
If a download would take longer than running the task, vx runs the task. 500 remote hits finish in 1.15 s instead of 3.12 s.
// the vx blog
Performance
Posts tagged performance.
CachingPerformanceWhat a run does not do
What a run does not do
A run does no cleanup at exit, never walks the shared store, and shows no "time saved" it did not measure.
CachingCache transfers wait on the network
Cache transfers wait on the network
Cache transfers mostly wait on the network, not a core. vx runs up to 64 at once, so 1,000 uploads to a cache 30 ms away take 2.5 s.
CachingA cache hit is a file copy
A cache hit is a file copy
A local cache hit is a file copy the kernel does. 1,000 hits of 96 KiB restore in 411 ms, and vx never hard-links.
PerformanceWhere a task run spends its time
Where a task run spends its time
We traced one workspace through vx, Turborepo 2.11.8 and Nx 23.3.0, cold and warm. A cold run is the tasks. A warm run is how little the tool does.
PerformanceCarry the scheduler's memory between CI runners
Carry the scheduler's memory between CI runners
A fresh CI runner has no run history, so it can't know which tasks are slow. One JSON file carries the learned times from runner to runner.
PerformanceA cold run asks the cache nothing
A cold run asks the cache nothing
With an empty cache, vx skips the lookups that would all miss. On 1,000 projects the first task starts 136 ms after vx run.
PerformanceWhich task runs first?
Which task runs first?
When more tasks are ready than workers, a runner has to pick. Five rules for picking, the graphs where each one wins and loses, measured with vx, and why recorded timings beat every rule that has to guess.
PerformanceHow many tasks at once? Count the cores you are given
How many tasks at once? Count the cores you are given
In a container, the CPU count a program sees is the host's. vx reads the limit the kernel enforces, so it never starts more tasks than you have cores.
PluginsA scheduler that learns from your runs
A scheduler that learns from your runs
@vzn/vx-history starts the longest chain first and keeps memory-hungry tasks apart, using times and memory from your past runs.
PerformanceWhy vx is fast: five decisions, not a trick
Why vx is fast: five decisions, not a trick
What vx adds to a run with nothing changed, with no daemon, and the five design choices behind that number.
PerformanceNo daemon, and still quick when nothing changed
No daemon, and still quick when nothing changed
vx has no background process watching your files. A run with nothing to do stays quick, and it can never act on a stale view of the tree.
InternalsTask priority in milliseconds, not 8.5 seconds
Task priority in milliseconds, not 8.5 seconds
On a 3,270-task graph, task priority took 8.5 seconds with set unions. Bitsets do it in single-digit milliseconds, and cache restores never take a slot from a build.
PerformanceBenchmarks you can re-run
Benchmarks you can re-run
One synthetic task graph, each tool in its own native config, every number one command away.