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Improve Download Memory Usage #61
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What's this do to throughput for download? In particular the warmup/first few runs?
@@ -129,18 +129,30 @@ fn handle_discovery_chunk( | |||
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/// Download operation specific state | |||
#[derive(Debug)] | |||
pub(crate) struct DownloadState {} | |||
pub(crate) struct DownloadState { | |||
current_seq: u64, |
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Can you not get away with an atomic here?
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Thanks, updated to AtomicU64.
if let Some(stream) = initial_chunk { | ||
let seq = handle.ctx.next_seq(); |
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start_seq
and seq
aren't connected anywhere here, should probably set start_seq
to seq
instead of hard coded to 1
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Thanks, we would have to set start_seq = seq+1. I have added a current_seq() function which will return 0 or 1 depending upon we called next_seq or not.
It didn’t help much since we were only doing 125 out of 3840 parts out of order. |
Description of changes:
Tokio.spawn
doesn't respect the spawn order, which can result in us downloading the firstnum_concurrency
parts in random order. For a workload of 5GB * 100 files, this can lead to very high memory usage, as seen in the diagram below. This PR refactors the exact part to be determined only once the task has been scheduled.Uploads can also have a similar issue where we read too many parts into memory. To fix that, we will need to refactor our scheduler to be smarter so that we only read the part when we have the permit. (Created: #60)
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