Hi Ben,
It turned out to be memory leak in my C++ wrapper on top of V8 - fixed it.
Thanks for the suggestion around using v8::HeapProfiler::TakeHeapSnapshot().
> On 24-Sep-2016, at 00:08, Ben Noordhuis <i...@bnoordhuis.nl> wrote:
>
> On Fri, Sep 23, 2016 at 12:54 PM, Abhishek Singh
> <singhabhishek....@gmail.com> wrote:
>> Hi,
>>
>> I noticed a V8 crash with following message:
>>
>>
>> <--- Last few GCs --->
>>
>> 251206 ms: Mark-sweep 1400.2 (1456.1) -> 1400.2 (1456.1) MB, 3688.5 / 0.0
>> ms [allocation failure] [GC in old space requested].
>> 254854 ms: Mark-sweep 1400.2 (1456.1) -> 1400.2 (1456.1) MB, 3648.2 / 0.0
>> ms [allocation failure] [GC in old space requested].
>> 258562 ms: Mark-sweep 1400.2 (1456.1) -> 1400.2 (1426.1) MB, 3707.6 / 0.0
>> ms [last resort gc].
>> 262315 ms: Mark-sweep 1400.2 (1426.1) -> 1400.2 (1426.1) MB, 3752.6 / 0.0
>> ms [last resort gc].
>>
>>
>> <--- JS stacktrace --->
>>
>> ==== JS stack trace =========================================
>>
>> Security context: 0x3c20e87ca141 <JS Object>
>> 1: OnHTTPGet [0x3c20e8704311 <undefined>:~64]
>> [pc=0x328074967a8e](this=0x94116b170d1 <JS Global Object>,req=0x6ba99d91ed1
>> <an Object with map 0x73dc030c4f9>,res=0x6ba99d91f29 <JS Object>)
>>
>> ==== Details ================================================
>>
>> [1]: OnHTTPGet [0x3c20e8704311 <undefined>:~64]
>> [pc=0x328074967a8e](this=0x94116b170d1 <JS Global Object>,req=0x6ba99d91ed1
>> <an Object with m...
>>
>>
>> What the application does is - it executes JS function call when an end user
>> fires a HTTP request and response object is written back to the end user.
>> Call volume was around 10K HTTP requests/sec(JS code being executed is
>> trivial) - snippet of it:
>>
>> function OnHTTPGet(req, res) {
>> res.body.msg = “Hello world”; // res is nested map exposed from C++ to JS
>> world
>> }
>>
>> ===
>>
>> I tried simulating behaviour on a standalone environment and could replicate
>> the problem, here is code to do that:
>> https://gist.github.com/abhi-bit/505538ac45d4b11014c3681e3bb74a2b
>>
>> What I noticed that my machine has probably 4GB of memory left but V8’s
>> memory footprint was around 1.6GB before the crash. To summarise my
>> questions:
>>
>> Is 10K request/sec(JS function calls/sec) too much for GC to handle in this
>> scenario? Any tunable to control this behaviour or am I doing wrong in
>> standalone code?
>
> Modulo bugs in the garbage collector the request rate shouldn't
> matter. Your application can not allocate faster than the collector
> can reclaim because it will simply block your application until it
> catches up. Not necessarily true for a truly concurrent GC but V8's
> is still stop-the-world when it has to be.
>
> A more likely cause is that you have a memory leak somewhere. Try
> making snapshots of the heap that you can inspect in Chrome DevTools;
> see HeapProfiler::TakeHeapSnapshot() in include/v8-profiler.h or
> https://github.com/bnoordhuis/node-heapdump for a more full-fledged
> example.
>
>> Why V8 mem_size could only grow upto 1.6GB, even when system has 4GB of
>> memory? I’ve seen similar problem in couchdb(map-reduce index based on top
>> of V8) as well, where app V8 binding crashed when footprint when close to
>> 1.6GB(but that with V8 3.23) - error dump looked like this:
>
> The default limit is ~1.6 GB. You can turn it up with
> --max_old_space_size or through
> Isolate::CreateParams::constraints::set_max_old_space_size().
>
> --
> --
> v8-users mailing list
> v8-users@googlegroups.com
> http://groups.google.com/group/v8-users
> ---
> You received this message because you are subscribed to the Google Groups
> "v8-users" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to v8-users+unsubscr...@googlegroups.com.
> For more options, visit https://groups.google.com/d/optout.
--
--
v8-users mailing list
v8-users@googlegroups.com
http://groups.google.com/group/v8-users
---
You received this message because you are subscribed to the Google Groups
"v8-users" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to v8-users+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
