Commit Graph

5 Commits

Author SHA1 Message Date
Emilio G. Cota
11b7b07f8a qdist: return "(empty)" instead of NULL when printing an empty dist
Printf'ing a NULL string is undefined behaviour. Avoid it.

Reported-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Message-Id: <1469459025-23606-4-git-send-email-cota@braap.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-08-03 18:44:56 +02:00
Emilio G. Cota
071d405477 qdist: use g_renew and g_new instead of g_realloc and g_malloc.
This is safer against overflow.  g_renew is available in all
version of glib, while g_realloc_n is only available in 2.24.

Signed-off-by: Emilio G. Cota <cota@braap.org>
Message-Id: <1469459025-23606-3-git-send-email-cota@braap.org>
[Rewritten to use g_new/g_renew. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-08-03 18:42:35 +02:00
Emilio G. Cota
f9dbc19e8b qdist: fix memory leak during binning
In qdist_bin__internal(), to->entries is initialized to a 1-element array,
which we then leak when n == from->n. Fix it.

Signed-off-by: Emilio G. Cota <cota@braap.org>
Message-Id: <1469459025-23606-2-git-send-email-cota@braap.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-08-02 12:03:58 +02:00
Paolo Bonzini
e9abfcb57f clean-includes: run it once more
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-06-16 18:39:03 +02:00
Emilio G. Cota
bf3afd5f41 qdist: add module to represent frequency distributions of data
Sometimes it is useful to have a quick histogram to represent a certain
distribution -- for example, when investigating a performance regression
in a hash table due to inadequate hashing.

The appended allows us to easily represent a distribution using Unicode
characters. Further, the data structure keeping track of the distribution
is so simple that obtaining its values for off-line processing is trivial.

Example, taking the last 10 commits to QEMU:

 Characters in commit title  Count
-----------------------------------
                         39      1
                         48      1
                         53      1
                         54      2
                         57      1
                         61      1
                         67      1
                         78      1
                         80      1
qdist_init(&dist);
qdist_inc(&dist, 39);
[...]
qdist_inc(&dist, 80);

char *str = qdist_pr(&dist, 9, QDIST_PR_LABELS);
// -> [39.0,43.6)▂▂ █▂ ▂ ▄[75.4,80.0]
g_free(str);

char *str = qdist_pr(&dist, 4, QDIST_PR_LABELS);
// -> [39.0,49.2)▁█▁▁[69.8,80.0]
g_free(str);

Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Message-Id: <1465412133-3029-9-git-send-email-cota@braap.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
2016-06-11 23:10:19 +00:00