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c-blake
batch
C2020–2026
c-blake / batch

batch

Generic batch system calls for Linux

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2Distinct people
7Mentions
1Explicit recommenders
26GitHub stars
REPOSITORY AT A GLANCE

What to know before exploring

What it is

Generic batch system calls for Linux

GitHub

Where it is used

No documented product use has been verified yet.

What people are saying

Yeah.. FlexSC / Soares is my favorite paper from OSDI 2010. The system call batching with "looped" multi-call they mention there relates to the roughly 30 line (not actually…

cb321 used a recommendation phrase. One indexed comment matches. This is a phrase match, not a verdict.

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Also in these discussions

No other repository is repeatedly linked in the same discussions.

This week on Hacker News

Nov 7–Nov 14 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/14/2026, 1:49:46 PM UTC.

No direct repository links were found in the indexed HN discussions over the past seven days. Older discussions are available below.

Mentions over time

HN mentions by year7 dated mentions

Observed mentions: 2020-11-26 20:02:32 UTC to 2026-01-25 12:04:31 UTC.

012342020-01-01 00:00:00 UTC to 2021-01-01 00:00:00 UTC (exclusive): 1 mentions; 0 submissions, 1 comments20202021-01-01 00:00:00 UTC to 2022-01-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2022-01-01 00:00:00 UTC to 2023-01-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2023-01-01 00:00:00 UTC to 2024-01-01 00:00:00 UTC (exclusive): 1 mentions; 1 submissions, 0 comments20232024-01-01 00:00:00 UTC to 2025-01-01 00:00:00 UTC (exclusive): 4 mentions; 0 submissions, 4 comments2025-01-01 00:00:00 UTC to 2026-01-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2026-01-01 00:00:00 UTC to 2027-01-01 00:00:00 UTC (exclusive): 1 mentions; 0 submissions, 1 comments. Incomplete calendar period.2026*

* An incomplete calendar period is marked with an outlined bar. Its count is not directly comparable with a full period.

Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.

View mention counts and date ranges
UTC ranges include their start and exclude their end. Select a period to filter the source evidence.
PeriodStart (UTC)End (exclusive, UTC)MentionsSubmissionsComments
20202020-01-01 00:00:00 UTC2021-01-01 00:00:00 UTC101
20212021-01-01 00:00:00 UTC2022-01-01 00:00:00 UTC000
20222022-01-01 00:00:00 UTC2023-01-01 00:00:00 UTC000
20232023-01-01 00:00:00 UTC2024-01-01 00:00:00 UTC110
20242024-01-01 00:00:00 UTC2025-01-01 00:00:00 UTC404
20252025-01-01 00:00:00 UTC2026-01-01 00:00:00 UTC000
2026 (partial)2026-01-01 00:00:00 UTC2027-01-01 00:00:00 UTC101

What Hacker News says

7 sources
cb321·Jan 25, 2026
One aspect of the question is that "permissions" are mostly regulated at the time of open and user-code should check for failures. This was a driving inspiration for the tiny 27 lines of C virtual machine in https://github.com/c-blake/batch that allows you to, e.g., synthesize a single call that mmaps a whole file https://github.com/c-blake/batch/blob/64a35b4b35efa8c52afb64... which seems like it would have also helped the article author.
In I built a 2x faster lexer, then discovered I/O was the real bottleneck
cb321·Jul 15, 2024
You might both still be interested in the tiny (EDIT: 27 lines! https://github.com/c-blake/batch/blob/9c7e07670ef1fd0e98687c...) little "virtual machine interpreter" I linked to. Per-interpreter loop overheads are below 100 CPU cycles on several CPUs on a generation of hardware similar to what https://www.usenix.org/system/files/atc20-gu.pdf was mentioning as 700-1000 cycles for microkernel IPC latencies. I'm not sure if the idea coheres with io_uring style dispatch (especially the emphasized polling mode), though.. maybe with some work. The reason I mentioned it after elcritch's RTOS mention is partly that the way the little interpreter has no backward jumps means there are no loops and so no halting problem issue. So, you can still embed conditional error handling logic in system call batches, but the overall call is bounded by the ti
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me of its component calls (that is, if they are bounded, anyway...). That might be a useful property for higher levels of the system to guarantee meeting a real-time budget in many situations with very low complexity. I'm not sure if any of this is original with that github repo, but I haven't seen it before in this specific context. Perhaps the most complete example of "adding a new sys_batch-based syscall" is https://github.com/c-blake/batch/blob/master/examples/total.... which adds a `mapall` that can mmap a whole file or fail trying (at a couple points) for the purpose of just totaling the bytes as an example calculation.
In Fusion – A hobby OS implemented in Nim
cb321·Jul 15, 2024
To either of you, whenever you are doing something new from scratch, it can be useful to consider the granularity of provided abstractions & services which khaledh seems to be doing. I see fusion only has like 8 syscalls presently. It's not in Nim, but along these lines ("how much" individual calls do), you might want to consider an approach like this: https://github.com/c-blake/batch to amortize costs of crossing expensive call boundaries.
In Fusion – A hobby OS implemented in Nim
cb321·Jan 30, 2024Recommendation phrase
Yeah.. FlexSC / Soares is my favorite paper from OSDI 2010. The system call batching with "looped" multi-call they mention there relates to the roughly 30 line (not actually looping) assembly language in my other comment here (https://news.ycombinator.com/item?id=39189135) and in a few ways pre-saged io_uring work. Anyway, a 20-line example of a program written against said interpreter is https://github.com/c-blake/batch/blob/1201eefc92da9121405b79... but that only needs the wdcpy fake syscall not the conditional jump forward (although that could/should be added if the open can succeed but the mmap can fail and you want the close clean-up also included in the batch, etc., etc.). I believe Cassyopia (also mentioned in Soares) hoped to be able to analyze code in user-space with compiler techniques to automagically generate such programs, b
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ut I don't know that the work ever got beyond a HotOS paper (i.e. the kinda hopes & dreams stage) and it was never clear how fancy the anticipated batches being. The Xen/VMware multi-calls Soares2010 also mentions do not seem to have inline copy/jumps, though I'd be pretty surprised if that little kernel module is the only example of it.
In On the Costs of Syscalls (2021)
cb321·Jan 30, 2024
Using https://github.com/c-blake/batch/blob/master/examples/closes... from the examples/ directory of https://github.com/c-blake/batch, I get: L2:bat/examples$ BATCH_EMUL=1 ./closes|awk '{print $3,$2,$1*$2}'|fitl -s0 -c,=,n,b -b100 1 2 3 $1= 3.815 *$2 + 695.6826 *$3 bootstrap-stderr-corr matrix 0.8872 -0.7856 0.04174 L2:bat/examples$ BATCH_EMUL=1 ./closes|awk '{print $3,$2,$1*$2}'|fitl -s0 -c,=,n,b -b100 1 2 3 $1= 4.528 *$2 + 695.3265 *$3 bootstrap-stderr-corr matrix 1.174 -0.7640 0.05302 L2:bat/examples$ a (695.3265 +- 0.05302)-(695.6826 +- 0.04174) -0.356 +- 0.067 # i.e. run-to-run consistent L2:bat/examples$ ./closes|awk '{print $3,$2,$1*$2}'|fitl -s0 -c,=,n,b -b100 1 2 3 $1= 779.67 *$2 + 48.861 *$3 bootstrap-stderr-corr matrix
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1.550 -0.7495 0.2023 L2:bat/examples$ ./closes|awk '{print $3,$2,$1*$2}'|fitl -s0 -c,=,n,b -b100 1 2 3 $1= 787.77 *$2 + 48.745 *$3 bootstrap-stderr-corr matrix 1.350 -0.6207 0.1635 L2:bat/examples$ a (48.861 +- 0.2023)-(48.745 +- 0.1635) 0.12 +- 0.26 # i.e. run-to-run consistent L2:bat/examples$ a (695.3265 +- 0.05302)/(48.745 +- 0.1635) 14.265 +- 0.048 # i.e. batching makes it 14X faster! One can go further to get a mean +- std.err of ~695.52 +- ~0.04 nanosec hot-cache time per syscall overhead or even do point-weighting there, but it's probably more important to check fit residuals for serial autocorrelation (very do-able with https://github.com/c-blake/fitl, EDIT: oh, and if you care `a` is basically shown in https://github.com/SciNim/Measuremancer/pull/12 which uses standard error propagation). The bigger point would not be ever more careful measurement of the cost if you do not, but rather the ease of "batchifying" if you do of any highly regular call interface similar to syscalls with high latency and also the "follow on" API design, granularity-wise. The inner code of a mini-assembly language letting you implement, say, open/fstat/mmap/close all in one syscall crossing is only about 30 lines of C. { Yes, yes..It could use multi-CPU-arch and syscall auditing integration.. and sure, ebpf & io_uring alter the Linux landscape these days }. Also, @exDM69 is very correct that pure hot cache-hot loop numbers are only one part of the cost story (https://news.ycombinator.com/item?id=39188551).
In On the Costs of Syscalls (2021)

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