From: Jeff King <peff@peff.net>
To: Duy Nguyen <pclouds@gmail.com>
Cc: Elijah Newren <newren@gmail.com>, Git Mailing List <git@vger.kernel.org>
Subject: Re: 2.18.0 Regression: packing performance and effectiveness
Date: Thu, 19 Jul 2018 13:04:00 -0400 [thread overview]
Message-ID: <20180719170400.GC4868@sigill.intra.peff.net> (raw)
In-Reply-To: <20180719151640.GA24997@duynguyen.home>
On Thu, Jul 19, 2018 at 05:16:42PM +0200, Duy Nguyen wrote:
> On Thu, Jul 19, 2018 at 07:57:37AM +0200, Duy Nguyen wrote:
> > I thought 2M was generous but I was obviously wrong. I'd like to see
> > the biggest delta size in this pack and whether it's still reasonable
> > to increase OE_DELTA_SIZE_BITS. But if it's very close to 4GB limit
> > then we could just store 64-bit delta size in a separate array.
>
> I realize now that these two options don't have to be mutually
> exclusive and I should provide a good fallback in terms of performance
> anyway.
Yeah, this is what I had assumed was happening in the original code. :)
> +void oe_prepare_delta_size_array(struct packing_data *pack)
> +{
> + int i;
> +
> + /*
> + * nr_alloc, not nr_objects to align with realloc() strategy in
> + * packlist_alloc()
> + */
> + ALLOC_ARRAY(pack->delta_size, pack->nr_alloc);
> +
> + for (i = 0; i < pack->nr_objects; i++)
> + pack->delta_size[i] = pack->objects[i].delta_size_;
> +}
This iterator should probably be a uint32_t, to match nr_objects.
The rest of the patch looks OK to me. From Elijah's failure report there
clearly is _some_ problem where we end up with a truncated write of a
delta. But I don't see it from code inspection, nor could I reproduce
it.
-Peff
next prev parent reply other threads:[~2018-07-19 17:04 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-18 22:51 2.18.0 Regression: packing performance and effectiveness Elijah Newren
2018-07-18 22:51 ` [RFC PATCH] fix-v1: revert "pack-objects: shrink delta_size field in struct object_entry" Elijah Newren
2018-07-18 22:51 ` [RFC PATCH] fix-v2: make OE_DELTA_SIZE_BITS a bit bigger Elijah Newren
2018-07-19 5:41 ` 2.18.0 Regression: packing performance and effectiveness Duy Nguyen
2018-07-19 5:49 ` Jeff King
2018-07-19 15:27 ` Elijah Newren
2018-07-19 15:43 ` Duy Nguyen
2018-07-19 5:44 ` Jeff King
2018-07-19 5:57 ` Duy Nguyen
2018-07-19 15:16 ` Duy Nguyen
2018-07-19 16:42 ` Elijah Newren
2018-07-19 17:23 ` Jeff King
2018-07-19 17:31 ` Duy Nguyen
2018-07-19 18:24 ` Duy Nguyen
2018-07-19 19:17 ` Jeff King
2018-07-19 23:11 ` Elijah Newren
2018-07-20 5:28 ` Jeff King
2018-07-20 5:30 ` Jeff King
2018-07-20 5:47 ` Duy Nguyen
2018-07-20 17:21 ` Elijah Newren
2018-07-19 17:04 ` Jeff King [this message]
2018-07-19 19:25 ` Junio C Hamano
2018-07-19 19:27 ` Junio C Hamano
2018-07-20 15:39 ` [PATCH] pack-objects: fix performance issues on packing large deltas Nguyễn Thái Ngọc Duy
2018-07-20 17:40 ` Jeff King
2018-07-21 4:23 ` Duy Nguyen
2018-07-23 21:37 ` Jeff King
2018-07-20 17:43 ` Elijah Newren
2018-07-20 23:52 ` Elijah Newren
2018-07-21 4:07 ` Duy Nguyen
2018-07-21 7:08 ` Duy Nguyen
2018-07-21 4:47 ` Duy Nguyen
2018-07-21 6:56 ` Elijah Newren
2018-07-21 7:14 ` Duy Nguyen
2018-07-22 6:22 ` Elijah Newren
2018-07-22 6:49 ` Duy Nguyen
2018-07-23 12:34 ` Elijah Newren
2018-07-23 15:50 ` Duy Nguyen
2018-07-22 8:04 ` [PATCH v2] " Nguyễn Thái Ngọc Duy
2018-07-23 18:04 ` Junio C Hamano
2018-07-23 18:38 ` Duy Nguyen
2018-07-23 18:49 ` Duy Nguyen
2018-07-23 21:30 ` Jeff King
2018-07-26 8:12 ` Johannes Sixt
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